What is kinetic energy

Answer:

w = 252.32 N

Explanation:

given data

balloon expand = 50 times its original size

we consider here  initially pressure and volume

pressure = 645 pa

volume = 0.10 m³

solution

as in isothermala process ideal gas

PV = mRT

P = [tex]\frac{mRT}{v}[/tex]

P = [tex]\frac{c}{v}[/tex]

here c is constant

so work done is express as

[tex]w = c \int\limits^{V2}_{V1} {\frac{dv}{v}}[/tex]  

w = [tex]c \times ln( \frac{v2}{v1})[/tex]

and we know c  = p1 × v1

so

w = p1 × v1 × [tex]ln (\frac{50v1}{v1} )[/tex]

w = 645 × 0.1 × ln(50)

w = 252.32 N

Answer:

Explanation:

I catch the ruler 5.7 cm from lower end that means my reaction time is equal to time of fall of ruler as free fall under gravity .

h = 1/2 gt²

t = [tex]\sqrt{\frac{2h}{g} }[/tex]

= [tex]\sqrt{\frac{2\times 5.7}{9.8} }[/tex]

= 1.078 s

= 1.1 s .

Answer:

The same momentum will be the best option.

Explanation:

Let's recall that the force will be express in terms of the momentum. We can write the force as the variation of the momentum over time.

[tex]F=\frac{dp}{dt}[/tex]

This is the force needed to stop the base ball or the bowling ball.

if we will choose the same kinetic energy it would imply an increase of momentum, because of the difference of the masses, and therefore an increase of the force. We do not want this.

Now, if we choose the same momentum the kinetic energy will increase, but the force will the same. We want the less force as possible to stop it, and we have the same at least.

Therefore the same momentum would be the best option.

I hope it helps you!

The best choice to catch and hold the bowling ball will be; with the same momentum

We know that formula for impulse is;

Impulse = Force x Time

And we know that change in momentum is equal to impulse. Thus;

Change in momentum = F × t

ΔP = F × t

F = ΔP/t

This formula represents the force required to stop the baseball or the bowling ball.

Now,  momentum is proportional to the square root of kinetic energy.

Now, since momentum is directly proportional to velocity, while kinetic energy is proportional to the square of the velocity, it means that if kinetic energy is quadrupled, then the momentum will become double.

Now, the collision in the question is completely inelastic and as such, all the bowling balls kinetic energy will be in inelastic collision, the kinetic energy is lost.

Formula for the kinetic energy in terms of the momentum here is;

K = p²/2m

Looking at it overall, we can say that the best choice to catch and hold the bowling ball will be with the same momentum since it results in lesser force.

Read more at;https://brainly.com/question/13994440

Answer:[tex]60^{\circ}[/tex]

Explanation:

Given

[tex]\mid\Vec{A}\mid=1[/tex]

[tex]\mid\Vec{B}\mid=2[/tex]

And [tex]A\cdot B=1[/tex]

We know [tex]\vec{A}\cdot \vec{B}=\mid\Vec{A}\mid\mid\Vec{B}\mid\cos \theta[/tex]

Where [tex]\theta[/tex] is the angle between them

Substituting the values

[tex]1=1\times 2\cos \theta[/tex]

[tex]\cos \theta =\dfrac{1}{2}[/tex]

[tex]\theta =60^{\circ}[/tex]

Thus the angle between [tex]A[/tex] and [tex]B[/tex] is  [tex]60^{\circ}[/tex]

Answer:

a

The speed of the quarterback backward is [tex]v_q = 0.08 \ m/s[/tex]

b

Known are

 [tex]m_Q , m_B , (v_{Bx})_i (v_{Qx})_f, (v_{Bx})_f[/tex]

Unknown

   [tex](v_{Qx})_f[/tex]

Explanation:

From the question we are told that

   The mass of the quarterback is [tex]m_Q = 80 \ kg[/tex]

    The mass of the ball is [tex]m_B = 0.43 \ kg[/tex]

     The speed of the ball is  [tex]v_{B x}= 15 \ m/s[/tex]

The law of momentum conservation can be mathematically represented as

       [tex]m_Q u_{Qx} + m_Bu_{Bx} = - m_{Q} v_{Qx} + m_B v_{Bx}[/tex]

Now at initial both ball and quarterback are at rest and the negative sign signify that the quarterback moved backwards after throwing the ball

  So

       [tex]m_Q v_{Qx} = m_B v_ {Bx}[/tex]

=>     [tex]v_{Qx} = \frac{m_Bv_{Bx}}{m_Q}[/tex]

substituting values

        [tex]v_q = \frac{0.43 * 15}{80}[/tex]

       [tex]v_q = 0.08 \ m/s[/tex]

Answer:

0.056 psi more pressure is exerted by filled coat rack than an empty coat rack.

Explanation:

First we find the pressure exerted by the rack without coat. So, for that purpose, we use formula:

P₁ = F/A

where,

P₁ = Pressure exerted by empty rack = ?

F = Force exerted by empty rack = Weight of Empty Rack = 40 lb

A = Base Area = 452.4 in²

Therefore,

P₁ = 40 lb/452.4 in²

P₁ = 0.088 psi

Now, we calculate the pressure exerted by the rack along with the coat.

P₂ = F/A

where,

P₂ = Pressure exerted by rack filled with coats= ?

F = Force exerted by filled rack = Weight of Filled Rack = 65 lb

A = Base Area = 452.4 in²

Therefore,

P₂ = 65 lb/452.4 in²

P₂ = 0.144 psi

Now, the difference between both pressures is:

ΔP = P₂ - P₁

ΔP = 0.144 psi - 0.088 psi

ΔP = 0.056 psi

Answer:

2.46 x 104

Explanation:

Solution

Recall that:

The retention time of a peak = 407 s

with a width at half-height of = 7.6 s

A compound is retained in 2.5 s.

resolution to be achieved = 1.5

Thus,

The number of plates (theoretical)= 16(tr2 / w2)

The R Resolution R= 0.589 Δtr / w1/2av = 0.589(17s) / 1/2(7.6s + 9.4s) = 1.18

Supposed that applied column contains 10,000 theoretical plates and the resolution of two peaks is 1.18

So if the column is replaced to obtain 1.5 resolution, the number of theoretical plates is needed is  stated below;

width at the base = 9.4 - 7.6 = 1.8; tr = 0.786

N = 5.55tr2 / w21/2 = 5.55 (0.7862/ 1.182) x 104

= 2.46 x 104

Therefore, required theoretical plates to achieve a resolution of 1.5 is 2.46 x 104

Answer:

W = 1.5 x 10⁶ J = 1.5 MJ

Explanation:

First, we calculate the potential difference between the given 2 points. So, we have:

V₁ = Electric Potential at Initial Position = 6.7 V

V₂ = Electric Potential at Final Position = - 8.9 V

Therefore,

ΔV = Potential Difference = V₂ - V₁ = -8.9 V - 6.7 V = - 15.6 V

Since, we use magnitude in calculation only. Therefore,

ΔV = 15.6 V

Now, we calculate total charge:

Total Charge = q = (No. of Electrons)(Charge on 1 Electron)

where,

No. of Electrons = Avagadro's No. = 6.022 x 10²³

Charge on 1 electron = 1.6 x 10⁻¹⁹ C

Therefore,

q = (6.022 x 10²³)(1.6 x 10⁻¹⁹ C)

q = 96352 C

Now, from the definition of potential difference, we know that it is equal to the worked done on a unit charge moving it between the two points of different potentials:

ΔV = W/q

W = (ΔV )(q)

where,

W = work done = ?

W = (15.6 V)(96352 C)

W = 1.5 x 10⁶ J = 1.5 MJ

Answer:

The mass of the ice added = 16.71 g

Explanation:

The heat gained by the ice is equal to the heat lost by the calorimeter cup and the water in the cup.

But for this question, the cup is said to be perfectly insulated, hence, there is no loss of heat from the calorimeter cup.

Heat gained by the ice = Heat lost by the 326 g of water.

Let the mass of ice be m

The heat gained by the ice = (Heat gained by ice in temperature from -5.5°C to 0°C) + (Heat used by the ice to melt at 0°C) + (Heat required for the melted ice to rise in temperature from 0°C to 15°C)

Heat gained by ice in temperature from -5.5°C to 0°C = mCΔT

m = unknown mass of ice

C = Specific Heat capacity of ice = 2.108 J/g°C

ΔT = change in temperature = 0 - (-5.5) = 5.5°C

Heat gained by ice in temperature from -5.5°C to 0°C = m×2.108×5.5 = (11.594m) J

Heat used by the ice to melt at 0°C = mL

m = unknown mass of ice

L = Latent Heat of fusion of ice to water = 334 J/g

Heat used by the ice to melt at 0°C = m×334 = (334m) J

Heat required for the melted ice or water now, to rise in temperature from 0°C to 15°C = mCΔT

m = unknown mass of water (which was ice)

C = Specific Heat capacity of water = 4.186 J/g°C

ΔT = change in temperature = 15 - 0 = 15°C

Heat required for the melted ice or water now, to rise in temperature from 0°C to 15°C = m×4.186×15 = (62.79m) J

Total heat gained by the ice = 11.594m + 334m + 62.79m = (408.384m) J

Heat lost by the water in the calorimeter cup = MCΔT

M = mass of water in the calorimeter cup = 326 g

C = specific heat capacity of water = 4.186 J/g°C

ΔT = change in temperature = 20 - 15 = 5°C

Heat lost by the water in the calorimeter cup = 326×4.186×5 = 6,823.18 J

Heat gained by the ice = Heat lost by the 326 g of water.

408.384m = 6,823.18

m = (6,823.18/408.384)

m = 16.71 g

Hope this Helps!!!

Answer:

Explanation:

Initial moment of inertia of the carousel + girl

I₁ = 110 + 44 x 1.7²

= 110 + 127.16

= 237.16 kgm².

final moment of inertia of carousel + girl

I₂ = 110 + 44 x d²

applying law of conservation of angular momentum

I₁ ω₁ = I₂ω₂

ω₁ and ω₂ are angular velocities of the carousel before and after .

237.16 x 3.4 = (110 + 44 x d²)x 5.4

806.34 = 594 + 237.6 d²

237.6 d² = 212.34

d²= .8936

d = .9453 m

Answer:

Given the potential, [tex] V = Ax^l+By^m+Cz^n+D [/tex]

The components of the electric field are:

[tex]E_x = \frac{-dV}{dx} = -Alx^l^-^1[/tex]

[tex]E_y = \frac{-dV}{dy} = - Bmy^m^-^1[/tex]

[tex]E_z = \frac{-dV}{dz} = - nCzn^n^-^1[/tex]

Let's calculate the potential difference for all given points.

[tex] V(0, 0, 0) = 10V => Ax^l+By^m+Cz^n+D = 10 [/tex]

[tex]=> D = 10[/tex]

[tex] V(1, 0, 0) = 4V => A + 10 = 4 [/tex]

Solving for A, we have:

[tex] A = 4 - 10 [/tex]

[tex] A = -6 [/tex]

[tex] V(0, 1, 0) = 6V => B + 10 = 6 [/tex]

Solving for B, we have:

[tex] B = 6 - 10[/tex]

[tex] B = -4 [/tex]

[tex] V(0, 0, 1) = 8V => C + 10 = 4 [/tex]

Solving for C, we have:

[tex] C = 8 - 10 [/tex]

[tex] C = -2 [/tex]

For all given points, let's calculate the magnitude of electric field as follow:

[tex]E_x (1, 0, 0) = 16 => - Alx^l^-^1 = 16[/tex]

[tex]Al = -16[/tex]

Solving for l, we have:

[tex]l = \frac{-16}{A}[/tex]

From above, A = -6

[tex]l = \frac{-16}{-6}[/tex]

[tex]l = \frac{8}{3}[/tex]

[tex] E_y (0, 1, 0) = 16=> Bmy^m^-^1 = 16 [/tex]

[tex]Bm = -16[/tex]

Solving for m, we have:

[tex]m = \frac{-16}{A}[/tex]

From above, B = -4

[tex]m = \frac{-16}{-4}[/tex]

[tex]m = 4[/tex]

[tex] E_y (0, 0, 1) = 16=> nCz^n^-^1 = 16 [/tex]

[tex]nC = - 16[/tex]

Solving for n, we have:

[tex]n = \frac{-16}{C}[/tex]

From above, C = -2

[tex]n = \frac{-16}{-2}[/tex]

[tex]n = 8[/tex]

Answer:

f = 7.57 Hz

Explanation:

To find the frequency of the damping oscillator, you first use the following formula for the angular frequency:

[tex]\omega=\sqrt{\omega_o-(\frac{b}{2m})^2}=\sqrt{\frac{k}{m}-(\frac{b}{2m})^2}\\\\[/tex]   (1)

k: spring constant = 2.65*10^4 N/m

m:  mass = 11.7 kg

b: damping coefficient = 4.50 Ns/m

You replace the values of k, m and b in the equation (1):

[tex]\omega=\sqrt{\frac{2.65*10^4N/m}{11.7kg}-(\frac{4.50Ns/m}{2(11.7kg)})^2}\\\\\omega=47.59\frac{rad}{s}[/tex]

Finally, you calculate the frequency:

[tex]f=\frac{\omega}{2\pi}=\frac{47.59}{2\pi}Hz=7.57\ Hz[/tex]

hence, the frequency of the oscillator is 7.57 Hz

Answer:

Final velocity of NFL line backer is 16.67 m/s.

Explanation:

From the question, we have following data about the NFL line backer:

Initial Speed of line backer = Vi = 0 m/s (Since, he starts from rest)

Distance covered by NFL line backer = s = 100 m

Time taken by the NFL line backer to complete 100 m sprint = t = 12 s

Acceleration of NFL line backer during sprint = a

Final Velocity of NFL line backer = Vf = ?

First we need to find the acceleration of the NFL line backer. For that purpose we will use 2nd equation of motion:

s = (Vi)(t) + (0.5)at²

using values:

100 m = (0 m/s)(12 s) + (0.5)(a)(12 s)²

100 m/72 s² = a

a = 1.39 m/s²

Now, we use 1st equation of motion to find Vf:

Vf = Vi + at

Vf = 0 m/s + (1.39 m/s²)(12 s)

Vf = 16.67 m/s

Complete and Clear Question:

A person puts a few apples into the freezer at -15°C to cool them quickly for guests who are about to arrive. Initially, the apples are at a uniform temperature of 20°C, and the heat transfer coefficient on the surfaces is 8 W/m2·K. Treating the apples as 9-cm-diameter spheres and taking their properties to be [tex]\rho =[/tex] 840 kg/m3,  [tex]c_{p} =[/tex] 3.81 kJ/kg·K, k = 0.418 W/m·K, and [tex]\alpha = 1.3 * 10^{-7} m^{2} /s[/tex], determine the center and surface temperatures of the apples in 1 h. Also, determine the amount of heat transfer from each apple. Solve this problem using analytical one-term approximation method (not the Heisler charts).

Answer:

Temperature at the center of the apple, T(t) = 11.215°C

Temperature at the surface of the apple, T(r,t) = 2.68°C

Amount of heat transfer from each apple, Q = 21.47 kJ

Explanation:

For clarity and easiness of expression, the calculations are handwritten and attached as a file. Check the attached files for the complete calculation.

Answer:

0.838

Explanation:

The ratio v/c of the speed v to the speed c of light in a vacuum is shown below:

Given that

[tex]\triangle t_0 = 24\ seconds[/tex] = time interval for one revolution

[tex]\triangle t = 44\ seconds[/tex] = time interval measured with speed v

based on the given information, the ratio v/c  of the speed v to the speed c of light in a vacuum is

[tex]\triangle t = \frac{\triangle t_0}{\sqrt{1 - \frac{v^2}{c^2}}}[/tex]

[tex]{\sqrt{1 - \frac{v^2}{c^2}}} = \frac{\triangle t_0}{\triangle t}[/tex]

Now squaring both the sides

[tex]\frac{v^2}{c^2} = 1 - \frac{(\triangle t_0)^2}{(\triangle t)^2}[/tex]

Now remove the squaring root from both the sides and putting the values

[tex]\frac{v}{c} = {\sqrt{1 - \frac{(\triangle t_0)^2}{(\triangle t)^2}[/tex]

[tex]= {\sqrt{1 - \frac{(24)^2}{(44)^2}[/tex]

= 0.838

Answer:

The speed of the second toy car after collision is [tex]v_2 = 0.155 \ m/s[/tex]

Explanation:

Let movement to the right be positive and the opposite negative

From the question we are told that

   The mass of the car is  [tex]m_1 = 15 \ g = \frac{15}{1000} = 0.015 \ kg[/tex]

    The initial velocity of the car is  [tex]u_1 = 24 \ cm /s = 0.24 m/s[/tex]

    The mass of the second toy car  [tex]m_2 = 21 g = 0.021 \ kg[/tex]

    The initial velocity of the car is [tex]u_2 = 31 \ cm/s =- 0.31 m/s[/tex]

    The final velocity of the first car is  [tex]v = 41cm/s = - 0.41 m/s[/tex]

     From law of momentum conservation we have that

     [tex]m_1 u_1 + m_2 u_2 = m_1 v_1 + m_2 v_2[/tex]

substituting values

       [tex](0.015* 0.24) +( 0.021 * -0.31) = (0.015 * -0.41 ) + 0.021 v_2[/tex]

      [tex]-0.00291 = -0.0615 + 0.021 v_2[/tex]

      [tex]v_2 = 0.155 \ m/s[/tex]

Answer: the answer is MIRANDA COOPER

Explanation:

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Answer:

A) E = 2550 J

B) K = 1325 J

C) t = 5,05 s

Explanation:

A) The total mechanical energy is given by the sum of the gravitational potential energy and the kinetic energy of the body:

[tex]E=U+K=mgh+\frac{1}{2}mv^2[/tex]  (1)

m: mass of the body = 2,0 kg

g: gravitational acceleration = 9,8 m/s^2

h: height = 125 m

v: initial velocity of the body = 10 m/s

You replace the values of all variables h, m, g and v in the equation (1):

[tex]E=(2,0kg)(9,8m/s^2)(125m)+\frac{1}{2}(2,0kg)(10m/s)^2=2550\ J[/tex]

the total mechanical energy is 2550 J

B) The kinetic  energy of the corp, when it is at a height of h/2 is given by:

[tex]K=\frac{1}{2}mv^2[/tex]

where

[tex]v=\sqrt{(v_x)^2+(v_y)^2}[/tex]

The x component of the velocity is constant in the complete trajectory, which is the initial velocity, that is, vo = vx

The y component is given by:

[tex]v_y^2=v_{oy}^2+2gy[/tex]

voy: vertical initial velocity = 0m/s

y: height = h/2 = 125/2 = 62.5 m

[tex]v_y=\sqrt{2g\frac{h}{2}}=\sqrt{2(9.8m/s^2)(62.5m)}=35m/s[/tex]

Then, you can calculate the velocity of the body and next, you can calculate the kinetic energy:

[tex]v=\sqrt{(10m/s)^2+(35m/s)^2}=36,40\frac{m}{s}\\\\K=\frac{1}{2}(2,0kg)(36,40m/s)^2=1325\ J[/tex]

C) The time that body takes in all its trajectory is:

[tex]t=\sqrt{\frac{2h}{g}}=\sqrt{\frac{2(125m)}{9,8m/s^2}}=5,05s[/tex]

Answer:

The answer is 5.05 hours.

Explanation:

If the plane has an airspeed of 203 km/h which only applies for air and not the ground speed, we can subtract the speed of the wind since it is a headwind in the directly opposite direction.

So the speed of the plane becomes 203 - 53.5 = 149.5 km/h which will give us the true airspeed of the plane and the ground speed as well.

From here we can calculate the time it will take to reach the city as

756 km / 149.5 km/h = 5.05 hours.

I hope this answer helps.

Answer:

Nope!

Explanation:

The amplitude of a wave does not affect the speed at which the wave travels. Both Wave A and Wave B travel at the same speed. The speed of a wave is only altered by alterations in the properties of the medium through which it travels.

HOPE IT HELPS :)

PLEASE MARK IT THE BRAINLIEST!

Answer:

T' = 0.9677T

Explanation:

The period of a pendulum is given by the following formula:

[tex]T=2\pi \sqrt{\frac{l}{g}}[/tex]

l: length of the pendulum

g: gravitational acceleration

If the length of the pendulum is decreased in 6.35% the length of the pendulum becomes:

[tex]l'=l-0.0635l=0.9365l[/tex]

The new period for a length of l' is:

[tex]T'=2\pi \sqrt{\frac{l'}{g}}=2\pi \sqrt{\frac{0.9365l}{g}}=\sqrt{0.9365}(2\pi \sqrt{\frac{l}{g}})=0.9677(2\pi \sqrt{\frac{l}{g}})\\\\T'=0.9677T[/tex]

hence, the new period is 0.9677T

Answer:

O reference point

Explanation:

A reference point is often given the value of zero to describe an object position on a straight line, or when it didn't move. If the object doesn't move, that means that there is no displacement, and it is a reference point. The answer to the question is reference point.

Answer:

a. Energy ≅ 43.2 kJ

b. Capacity of battery = 1600-mAh

Explanation:

average voltage value = (9 + 6)/2 = 15/2 = 7.5

current = 20 mA = 20 x [tex]10^{-3}[/tex]

time duration = 80 hrs = 80 x 60 x 60 = 288000 sec

If the current is assumed to be constant, then the energy delivered is the product of voltage across, current delivered and the time duration during which it is delivered.

Energy delivered by battery = 7.5 x 20 x [tex]10^{-3}[/tex]  x 288000 = 43200 J

Energy ≅ 43.2 kJ

If the battery is considered dead when it reaches 6-v, then that means that at 6-v, there is no potential difference between them.

capacity of flashlight battery is the product of current delivered and the time duration of delivery.

capacity =  20-mA x 80-hr = 1600-mAh

Answer:

as centripatal force acts upon an object moving at a circle in constant speed de force acts always inwards as de velocity of object is directed tangent to de circle de force can accelerate de object by changing its direction bt not actually de speed

The two quantities are closely related, but the cause/effect is the other way around.

-- The centripetal force is caused by something outside this discussion, not by the object.

-- The centripetal force acting on the object determines the object's centripetal acceleration.

-- The centripetal acceleration is the cause of whatever the object's velocity (speed and direction) turns out to be.

-- It's the centripetal acceleration that has the effect on the object's velocity.  

As an example, you wouldn't say that the orbiting of a TV satellite is what causes the Earth's centripetal force that acts on it.

Answer:

1. The electric potential at any point in space, is the work done in moving a unit charge from infinity to that point.

2.The electric potential varies radially by decreasing as the distance from the electric field increases.

Explanation:

1. The electric potential at any point in space, is the work done in moving a unit charge from infinity to that point. It is defined mathematically as, V = W/q where V = electric potential, W = work done in moving charge q into electric field and q = charge. For the work done of moving a charge q into an electric field of charge q' at a distance r between them, W = kqq'/r and work done per unit charge in moving q in electric field is V = W/q = kqq'/r ÷q = kq'/r, Also, for an electric field, E, V = ∫E.dr where r is the direction moved by the charge in the electric field.

2. Since the electric potential V = kq'/r, V ∝ 1/r since k and q' are constant. So, the electric potential varies radially by decreasing as the distance from the electric field increases.

Explanation:

It is given that,

Mass of the object, m = 350 g = 0.35 kg

Spring constant of the spring, k = 5.2 N/m

Amplitude of the oscillation, A = 10 cm = 0.1 m

Frequency of a spring mass system is given by :

[tex]f=\dfrac{1}{2\pi}\sqrt{\dfrac{k}{m}} \\\\f=\dfrac{1}{2\pi}\sqrt{\dfrac{5.2}{0.35}} \\\\f=0.613\ Hz[/tex]

Time period:

[tex]T=\dfrac{1}{f}\\\\T=\dfrac{1}{0.613}\\\\T=1.63\ s[/tex]

Maximum velocity in the spring is given by :

[tex]v=A\omega[/tex]

[tex]v=A\sqrt{\dfrac{k}{m}} \\\\v=0.1\times \sqrt{\dfrac{5.2}{0.35}} \\\\v=0.38\ m/s[/tex]

The maximum force acting in the spring is :

[tex]F=-kx\\\\F=kA\\\\F=5.2\times 0.1\\\\F=0.52\ N[/tex]

Hence, this is the required solution.

Answer:

Explanation:

The magnitude of the electric force on this charged particle A depends upon the following

5. the distance between the point charge Q and the charged particle A

8. the amount of the charge on the point charge Q

9. the magnitude of charge on the charged particle A

Answer:

A₁/A₂ = 0.136

Explanation:

The power radiated by a filament bulb is given by the following formula:

E = σεAT⁴

where,

E = Emissive Power

σ = Stephen Boltzman Constant

ε = emissivity

A = Area

T = Absolute Temperature

Therefore, for bulb 1:

E₁ = σε₁A₁T₁⁴

And for bulb 2:

E₂ = σε₂A₂T₂⁴

Dividing both the equations:

E₁/E₂ = σε₁A₁T₁⁴/σε₂A₂T₂⁴

According to given condition, the emissive power and the emissivity is same for both the bulbs. Therefore,

E/E = σεA₁T₁⁴/σεA₂T₂⁴

1 = A₁T₁⁴/A₂T₂⁴

A₁/A₂ = (T₂/T₁)⁴

where,

T₁ = 2800 K

T₂ = 1700 K

Therefore,

A₁/A₂ = (1700 K/2800 K)⁴

A₁/A₂ = 0.136