Power

An electric bulb is rated as $220 \mathrm{V}$ and $80 \mathrm{W}$. When it is operated on $110 \mathrm{V}$, the power rating would be:

Which of the following graphs represent constant non zero power?

Star$A$ has radius $r$ surface temperature $T$ while star$B$ has radius$4r$and surface temperature $\frac{T}{2}$ The ratio of the power of two stars,$P_A: P_B$is (a) 16:1 (b) 1:16 IMP PMT 200
(d) 14
(c) 1:1

A force of $\left(3\hat{\mathrm{i}}+4\hat{\mathrm{j}}+5\hat{\mathrm{k}} \right) \mathrm{N}$ acts on a body for $2 \mathrm{s}$ and produces a displacement of $\left(2\hat{\mathrm{i}}+3\hat{\mathrm{j}}+2\hat{\mathrm{k}}\right)$ m. Calculate the power

If the unit of force were $10 \mathrm{N}$, that of power were $1 \mathrm{MW}$ and that of time were $1 \mathrm{millisecond}$ then the unit of length would be

A block of mass $M$ is allowed to slide down a fixed smooth inclined plane of angle $\theta$ and length $l$. What is the power developed by the force of gravity when the block reaches the bottom?

A car of mass $m$ is moving along a circular track of radius $r$ with a speed which increases linearly with time $t$ as $v=kt$, where $k$ is a constant. The instantaneous power delivered by agent applying the force is

Force acting on a particle varies with the distance travelled by the particle as $F\propto \frac{1}{{\left(x\right)}^{{\displaystyle \frac{1}{3}}}}$ then power due to this force varies with $x$ as :

If the blocks shown in the figure are released from rest, what is the power delivered by the tension in the string to the $2 \mathrm{kg}$ block in first $2 \mathrm{s}$?

A motor is used to lift water from a well of depth $10 \mathrm{m}$ and to fill a water tank of volume $30{ \mathrm{m}}^3$ in $10$ minutes. The tank is at a height of $20 \mathrm{m}$ above ground. If $20\%$ of energy is wasted, the power of the motor is (in $\mathrm{kW}$)

The power output from a certain experimental car which is designed in shape like a cube is proportional to the mass $m$ of the car. The force of air friction on the car is proportional to $A{v}^2$, where $v$ is the speed of the car and $A$ the cross sectional area. On a level surface the car has a maximum speed $v_{\max }$. Assuming that all geometrically similar versions of this design have the same density, then which of the following is true?

Joule is the S.I unit of power.

A person who weighs $300 \mathrm{N}$ runs up a flight of stairs in $3.0 \mathrm{s}$. Their gain in height is $3.0 \mathrm{m}$. Calculate the power against the force of the gravity.

What will be the power delivered by all the forces acting on the bob of a pendulum when it is making angle $30°$ with the verticle? If it is released from a position where it makes an angle $60°$ with the verticle from rest. The mass of the bob is $1 \mathrm{kg}$ and length is $1 \mathrm{m}$. ($g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

Water falls down a $500.0 \mathrm{m}$ shaft to reach a turbine which generates electricity. How much water must fall per second in order to generate $1.00\times {10}^9$ watts of power ? (Assume $50\%$ efficiency of conversion and $g=10 \mathrm{m} {\mathrm{s}}^{-1}$)

A girl of mass $50 \mathrm{kg}$ swinging on a cradle. If she moves with a velocity of $2 \mathrm{m} {\mathrm{s}}^{-1}$ upwards in a direction making an angle $60°$ with the vertical, then the power generated is $\left(g=9.8 \mathrm{m} {\mathrm{s}}^{-2}\right)$

$1$ Horse Power (HP) $=$ ..... Watt.

The SI unit of power is .....

The $K\mathit{.}E\mathit{.}$ acquired by a mass $m$ in travelling a certain distance $d$, starting from rest, under the action of a constant force is directly proportional to:

A box is moved along a straight line by a machine delivering constant power. The distance traversed by the body in time $t$ is proportional to