Question 4 :
If $v$, $P$ and $E$ denote the velocity, momentum and kinetic energy of the particle, then:<br/>
Question 7 :
Assertion: Kilowatt Hour is the unit of electric power
Reason: KWH is a commercial unit used for expressing consumed electrical energy.
Question 8 :
1 kilowatt-hour is the amount of .... by 1000 watt electric appliance when it operates for one hour.
Question 14 :
Fill in the blanks:One kilowatt is equal to ________ horse power.
Question 16 :
An X-ray tube is run at 50 kV.. the current flowing in it is 20 mA. The power of the tube is:
Question 19 :
A man can lift a block of mass of 50 kg up to a height of 2 m in 2 seconds. Calculate the power developed by the man to lift the block.
Question 20 :
Which of the following must be known in order to determine the power output of an automobile? <br>
Question 25 :
What does the slope of work-time curve at any instant represent?
Question 27 :
In our household applications, commercial unit of electricity is used. One unit is equal to:
Question 28 :
An engine develops 10 kW of power. How much time will it take to lift a mass of 200kg to a height of 40m (g = 10 $ms^{-2}$)?
Question 30 :
How much energy does a 60W electric bulbtransfer in 1 minute?
Question 32 :
If a man of $30$ kilograms climbs stairs in $4$ seconds when height of stairs is $5$ meters, power output produced will be:<br/>
Question 34 :
The power of a crane is 6.25 kW. How much mass of coal it can lift in 1 hour from a mine of 100 m depth? The efficiency of the crane is 80% and $g = 10 \ m s^{-2}$.
Question 36 :
If the force applied is $F$ and the velocity gained is $v$, then the power developed is:
Question 37 :
An engine lifts a load of $1200\ N$ from a depth of $200 \ m$ in 4  minutes bringing it to the ground level. The power developed by the engine is:
Question 41 :
Mohan uses one television of $100$ W for $10$ hrs how much energy is consumed by Mohan.
Question 42 :
Which of the following can be used to express energy? Symbols have their usual meanings for the units of physical quantities.<br/>(i) Wh   (ii) VC    (iii) VAs$^2$  (iv)  A$^2\Omega$s<br/>
Question 44 :
A car of mass $2,000 kg$ is lifted up a distance of $30 m$ by a crane in $1\ minute$. A second crane does the same job in $2\ minutes$.The power supplied by first crane is:
Question 45 :
A man weighing 600 N carries a load of 150 N up the stairs 6 m high in 15 seconds. His power will be:
Question 47 :
A juggler throws continuously balls at the rate ofthree in each second each with a velocity of $10\ ms^{-1}$. If the mass of each ball is $0.05\ kg$ hispower is:
Question 49 :
A machine gun fires $420$ bullets $per\ minute$. The velocity of each of the bullets is $300 m s^{-1}$ and the mass of each bullet is $1 gm$. The power of machine gun is:
Question 50 :
If the power of the motor of a water pump is $3\ kW$, then the volume of water that can be liftedto a height of $10\ m$ in one minute by the pump is ($g= 10 \ m /s^{2}$) :
