MCQ
The temperature of the body is increased from $-73^o C\, to \,327^o C$, the ratio of energy emitted per second is :
- A$1:3$
- ✓$1:81$
- C$1:27$
- D$ 1:9$
✓
Answer
Correct option: B.
$1:81$
b
${T_1} = - 73 + 273 = 200K$
${T_1} = - 73 + 273 = 200K$
${T_2} = 327 + 273 = 600\;K$
Energy per second $P\left( { = \frac{Q}{t}} \right) \propto {T^4}$
$\Rightarrow \frac{{{P_2}}}{{{P_1}}} = {\left( {\frac{{{T_2}}}{{{T_1}}}} \right)^4} = {\left( {\frac{{600}}{{200}}} \right)^2} = 81$
$\frac{{{P_1}}}{{{P_2}}} = \frac{1}{{81}}$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
The velocity $(v)$-time $(t)$ graph for a particle moving along $x$-axis is shown in the figure. The corresponding position $(x)$ - time $(t)$ is best represented by
→A body of mass $'m'$ is launched up on a rough inclined plane making an angle of $30^{\circ}$ with the horizontal. The coeffcient of friction between the body and plane is $\frac{\sqrt{x}}{5}$ if the time of ascent is half of the time of descent. The value of $x$ is ..... .
→A car is moving on an overbridge of radius $R$ with a constant speed $v$. As the car is descending on the overbridge from point $B$ to $C,$ the normal reaction on it due to bridge
→A particle moves with constant angular velocity in circular path of certain radius and is acted upon by a certain centripetal force $F$. if the angular velocity is kept same but the radius of the path is halved, the new force will be
→A piece of ice falls from a height $h$ so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of $h$ is
→[Latent heat of ice is $3.4 \times 10^{5}\; J / k g$ and $g=10\; N / kg ]$
A particle starts from rest at $x=0\; m$ with an acceleration of $1 \,m / s ^2$. At $t = 5\;s _{ s }$ it receives an additional acceleration in the same direction as its motion. At $t =10\; s$ its speed and position are $v$ and $x$, respectively. Had the additional acceleration not been provided, its speed and position would have been $v _0$ and $x _0$, respectively. It is found that $x - x _0$ is $12.5 \,m$. Then one can conclude that $v - v _0$ is .............. $\,m / s$
→One litre of oxygen at a pressure of $1\, atm$ and two litres of nitrogen at a pressure of $0.5\, atm$ are introduced into a vessel of volume $1L$. If there is no change in temperature, the final pressure of the mixture of gas (in $atm$) is
→The diameter of two pistons of a hydraulic press are $0.1\,\, m$ and $0.6\,\, m$ respectively. Advantage of the hydraulic press assuming effort is applied directly on pump plunger
→Two passenger trains moving with a speed of $108\, km/hour$ cross each other. One of them blows a whistle whose frequency is $750 Hz.$ If sound speed is $330 m/s,$ then passengers sitting in the other train, after trains cross each other will hear sound whose frequency will be .... $Hz$
→When an object covers equal distances in equal time intervals, then its speed is: