Question 1 :
An X-ray tube is run at 50 kV.. the current flowing in it is 20 mA. The power of the tube is:
Question 2 :
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 8 :
A machine gun fires $240$ bullets $per\ minute$ with a certain velocity. If the mass of each bullet is $10 gm$ and the power of the gun is $7.2 kW$, the velocity with which each bullet is fired must be:
Question 10 :
A house uses 7 tubelight of 50 W each for 5 hours a day. The electrical energy consumption for one day is:
Question 11 :
A boy of mass $40\ kg$ runs up a flight of $15$ steps each $15\ cm$ high in $10s$.Find the power developed by him: Take $g=10N$ $kg^{-1}$
Question 12 :
What should be the power of an engine required to lift 90 metric tonnes of coal per hour from a mine whose depth is 200 m?<br>
Question 13 :
A boy of mass $40kg$ runs upstairs and reaches the roof at height $8m$ in $5s$. $($Take $\ g=10ms^{-2})$ Calculate the power spent by boy.
Question 14 :
An elevator is designed to lift a load of 1000 kg through 6 floors of a building averaging 3.5 m per floor in 6 sec. Power of a elevator neglecting other losses will be:
Question 15 :
Gravitational potential difference between surface of a planet and a point situated at a height of $20m$ above its surface is $2 joule/kg$. If gravitational fieldis uniform, then the work done in taking a $5kg$ bodyof height $4$ meter above surface will be :-
Question 16 :
How many kilograms will a man working at the power of 100 W, be able to lift at<br>constant speed of 1 $m s^{-1}$ vertically ? $(g = 10 m s^{-2})$<br><br><br>
Question 17 :
Compute the power at which a 250 g squirrel will climb up on a tree at a rate of 0.5 $ms^{-1}$ against the force of gravity? (given $g = 10 \ ms^{-2}$)
Question 18 :
The gravitational intensity a region is $10\left ( \hat{i}-\hat{j} \right )N/kg$. The work done by thegravitational force to shift slowly a particle ofmass $1\ Kg$ from point $(1m, 1m)$ to a point $(2m, -2m)$ is<br>
Question 19 :
A 10 m long nichrome wire having $80\Omega$ resistance has current carrying capacity of 5 A. This wire can be cut into equal parts and equal parts can be connected in series or parallel. What is the maximum power which can be obtained as heat by the wire from a 200 V mains supply? (in KW)
Question 20 :
Assertion: Total energy is negative for a bound system.
Reason: Potential energy of a bound system is negative and more than kinetic energy.
