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Which of the following is not a unit of energy? (1) joule (2) newton metre (3) kilowatt (4) kilowatt-hour

Answer: (3) kilowatt In physics, we can define energy as the capacity to do work. The SI unit of energy is joules (J). kilowatt is the unit of... View Article

Which of the following is not an example of zero work? (1) The work done by the tension in the string, when a body tied with the string move along a circular path (2) When a horse pulls a cart on a level road. (3) The work done by a coolie when he travels on a horizontal platform, with a load on his head. (4)When a person holds some amount of load but, does not move from his position.

Answer: (2) When a horse pulls a cart on a level road Zero work is defined when force and displacement are perpendicular to one another and... View Article

A truck moves at a steady speed on a horizontal road. What is the work done by the road on the truck?

The work is zero because while the truck does have a displacement over time, the force of the road (the normal force) is perpendicular and so the... View Article

In a steady state, what happens to the temperature of each part of the rod?

In a steady state, the temperature of each part of the rod is constant but not the same. Steady-state is the state when a conductor reaches a... View Article

On acceleration-time graph, a horizontal line indicates:

A horizontal line on a acceleration- time graph indicates that object has constant acceleration.... View Article

A boy throws up a ball in a stationary lift and the ball returns to his hands in 10 s. Now if the lift starts moving up at a speed of 5 m/s. The time taken for a ball thrown straight up to return to his hands is:

The uniform velocity of the lift does not affect the relative velocity of the ball with respect to the boy. So, the ball will still return in 10 s.... View Article

Which of the following is an example of heat pump?

A) Evaporator B) Double pipe heat exchanger C) Refrigerator D) None of the above The correct option is C) Refrigerator. A heat pump is defined... View Article

The second law of thermodynamics can be given as __________.

According to the second law of thermodynamics, for any spontaneous process the entropy of the universe increases.... View Article

Kelvin- Planck statement states that

Kelvin- Planck statement states that it is impossible to construct a device that operates on a cycle and produces no other effect than the... View Article

Which one of the following is not an example of the second law of thermodynamics?

CO2 is exhaled as a by-product of aerobic respiration is not an example of second law of thermodynamics.... View Article

Efficiency of Carnot engine working between ice point and steam point would be

Carnot engine was first proposed by Leonard Carnot. It is a theoretical thermodynamic cycle. The cycle that is used for estimating the maximum... View Article

In the following x-t graph, which path represents the displacement

Shortest path is displacement.... View Article

The graph represents the velocity time for the first 4 seconds of motion. The distance covered is

The distance covered = area under the curve = (1/2) x 4 x 15 = 30 m... View Article

Refrigerator transfers heat from the cold cooling coils to warm surroundings. Which law of thermodynamics favours this process?

In a refrigerator, external work is done by the compressor for the transfer of heat from the cold cooling coils to warm surroundings. Hence, the... View Article

A person goes from his home to his office taking one hour. There he works for 2 hours and then in half hour reaches home back. A representative displacement-time graph is

Take the reference point home as the origin. 1 hour: With respect to home the person moves to office: Motion is along +x axis. 2 hours: He stays... View Article

Which of the heat engine is not possible?

A heat engine with 100 % efficiency is not possible. For efficiency of heat engine η = 1- t2/ t1, either t2= 0 or t1= ∞ both these conditions can... View Article

In a heat engine the ratio of net work done per cycle by the engine to the total amount of heat absorbed per cycle by the working substance from the source is known as

In a heat engine the ratio of net work done per cycle by the engine to the total amount of heat absorbed per cycle by the working substance from... View Article

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