Question 2 :
The power of a pump takes 10 s to lift 100 kg of water tank situated at a height of 20 m is:
Question 4 :
A particle moves along the $x-$axis from $x =x_{1}$ to$x =x_{2}$ under the influence of a force given by $F= 2x$. Work done in the process is
Question 5 :
The power of a motor pump is $2\  kW$. How much water per minute the pump can raise to a height of 10 m? $(Given \:g = 10 \: m \: s^{-2})$<br/>
Question 6 :
Assertion: Total energy is conserved in moving a satellite to higher orbit.
Reason: Sum of change in PE and KE is same in magnitude and opposite in nature
Question 10 :
Assertion: Kilowatt Hour is the unit of electric power
Reason: KWH is a commercial unit used for expressing consumed electrical energy.
Question 13 :
Which of the following must be known in order to determine the power output of an automobile? <br>
Question 14 :
An object is thrown vertically upwards. As it rise, its total energy
Question 15 :
How much energy does a 60W electric bulbtransfer in 1 minute?
Question 18 :
When a work of 1 joule is done in 1 s, the power is:<br/><br/>
Question 19 :
If a force F is applied an a body and it moves with a velocity v, the power will be:
Question 20 :
Six electric appliances of 100 watts each are used for 6 hours. The electrical energy consumed is:
Question 21 :
If Rahul has done the same amount work in less time compared to Rohan then:
Question 22 :
The velocity acquired by a charged particle of mass $m$ and charge $Q$ accelerated from rest by a potential of $V$ is
Question 24 :
Find the energy in kWh consumed in 10 hours by four devices of power 500 W each.<br/>
Question 26 :
Two particles A and B having different masses are projected from a tower with same speed. A is projected vertically upward and B vertically downward. On reaching the ground:
Question 28 :
Mohan uses one television of $100$ W for $10$ hrs how much energy is consumed by Mohan.
Question 29 :
A washing machine rated $300W$ is operated one and half an hour/day. If the cost of units is Rs.$3.50$, find the cost of energy to operate a washing machine for the month of September.
Question 31 :
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 second crane is:
Question 34 :
Coolie A takes $1$min to raise a box of mass m through a height of $2.0$m. another coolie B takes $30$s for the same job. Which one has greater power?
Question 35 :
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 36 :
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 37 :
The minimum level of water in the reservoir of a hydroelectric dam is:<br/>
Question 38 :
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 39 :
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 ($g= 10 \ m /s^{2}$) :
Question 41 :
A planet whose mass and radius are both half of that of earth. Acceleration due to gravity(g) at its surface should be:
Question 42 :
An agent does $4$ J of work in $2$ s. Find the power of the agent.
Question 44 :
State whether the given statement is True or False :The potential energy of a free falling object decreases progressively.<br/>
Question 46 :
A stone of mass $m$ initially at rest and dropped from a height $h$, strikes the surface of the earth with a velocity $v$. If the gravitational force acting on the stone is $W$, then which of the following identities is correct?
Question 47 :
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 49 :
Assertion: A resistor of resistance R is connected to an ideal battery. If the value of R is decreased, the power dissipated in the circuit will increase.
Reason: The power dissipated in the circuit is directly proportional to the resistance of the circuit.