Tag: energy : forms and sources

Questions Related to energy : forms and sources

The work done by the external forces on a system equals the change in:

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. Total energy

  2. Kinetic energy

  3. Potential energy

  4. None of these

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Correct Option: B
Explanation:
Any work done on a body changes in is potential energy, as we deduce
from work energy theorem.
$W _T= \triangle K.E$

Find the change in internal energy in joulewhen 10$\mathrm { g }$ of air is heated from $30 ^ { \circ } \mathrm { C }$ to $40 ^ { \circ } \mathrm { C }$$( \mathrm { c } = 0.172 \mathrm { kcal } / \mathrm { kg } / \mathrm { KJ } = 4200 \mathrm { J } / \mathrm { kcal } )$

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. $62.24 J$

  2. $72.24 J$

  3. $52.24 J$

  4. $82.24 J$

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Correct Option: A

The energy generated in stars is because of

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. radioactivity

  2. nuclear fission

  3. nuclear fusion

  4. photo electric phenomenon

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Correct Option: C
Explanation:

Energy is produced in a star's center, where pressures are enormous and temperatures reach 27 million°F (15 million°C). This causes nuclear fusion—atoms of hydrogen are ripped apart and fuse (join) to form helium. These reactions release vast amounts of energy, which makes the star shine.

What will be the potential energy of a body of mass 5 kg kept at a height of 10 m ?

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. 50 J

  2. 0.5 J

  3. 500 J

  4. 25 J

Show answer
Correct Option: C
Explanation:

Answer is C.

Potential energy is energy stored in an object. This energy has the potential to do work. Gravity gives potential energy to an object. This potential energy is a result of gravity pulling downwards. The gravitational constant, g, is the acceleration of an object due to gravity. This acceleration is about 10 meters per second on earth. The formula for potential energy due to gravity is PE = mgh. As the object gets closer to the ground, its potential energy decreases while its kinetic energy increases. 
In this case, a body of mass 5 kg kept at a height of 10 m. So the potential energy is given as 5 * 10 *10 = 500 J.
Hence, the potential energy of a body of mass 5 kg kept at a height of 10 m is 500 J.

Define one kilo-calorie of heat.

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. $1^0C$

  2. $2^0C$

  3. $3^0C$

  4. $4^0C$

Show answer
Correct Option: A
Explanation:

One kilo-calorie is defined as the amount of heat required to raise the temperature of one kilogram of water by 1 °C. 

What physical quantity does the electron volt(eV) measure?

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. Charge

  2. Force

  3. Energy

  4. Current

Show answer
Correct Option: C
Explanation:

Electron volt or $eV$ is the unit of energy (electrical energy). $1\ eV = 1.6 \times 10⁻¹⁹ $ coulombs (charge of an electron) $\times $ 1 volt.

The SI unit of energy is:

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. newton

  2. pascal

  3. joule

  4. watt

Show answer
Correct Option: C
Explanation:

As energy is defined via work so,the SI unit for energy is the same as the unit of work that is joule (J)

When heated, molecules absorb ____ and their capacity to do ____ increases.

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. Work ,energy

  2. Energy ,work

  3. Heat, work

  4. Energy ,heat

Show answer
Correct Option: B
Explanation:

Energy is defined as the capacity to do work.

1 kilowatt hour $=$ ___________ .

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. $10.6 \times 10^6$Joule

  2. $3.6 \times 10^6$Joule

  3. $30.6 \times 10^6$Joule

  4. $3.6 \times 10^5$Joule

Show answer
Correct Option: B
Explanation:

The kilowatt hour is a unit of energy equal to 1,000 watt-hours, or 3.6 megajoule. If the energy is being transmitted or used at a constant rate (power) over a period of time, the total energy in kilowatt-hours is the product of the power in kilowatts and the time in hours.
1 kilowatt hour $= 1000 \times 3600 joule = 3.6 \times 10^{6}\ J$

The capacity of a body to do work is called ______ .

physics energy : forms and sources concept of energy energy for everything forms of energy

  1. Stamina

  2. Potential

  3. Velocity

  4.  Energy

Show answer
Correct Option: D
Explanation:

Energy is the capacity of a physical system to perform work. Energy exists in several forms such as heat energy, kinetic or mechanical energy, light energy, potential energy, electrical energy, or other forms. According to the law of conservation of energy the total energy of a system remains constant, though energy may transform into another form.
The SI unit of energy is the joule (J) or newton-meter (N-m). Joule is also the SI unit of work.