Tag: work and energy

Questions Related to work and energy

Which one is not a unit of energy.

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. Electron-volt

  2. Joule

  3. Calorie

  4. Watt

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Correct Option: C

How many joules are equivalent to $1$ unit of electricity.

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. $3.6\times{10}^{3}$

  2. $3.6\times{10}^{4}$

  3. $3.6\times{10}^{5}$

  4. $3.6\times{10}^{6}$

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Correct Option: D

A body of $1000 kg$ moving with $0.3m/s$ in +x direction. A hole is present at the bottom of body such that, mass is dropping at rate of $20 gm/sec$, inn -y direction. Find out force exerted by ejecting mass on body.

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. 0.4 N

  2. 0 N

  3. 0.6 N

  4. None of these

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Correct Option: A

Work done charge of mass 2 Kg due to external force against electrostatics force is - 10 J if charge is displaced from A to B. Velocity of charge at point A is 4m/s and at B is 2m/s then find difference is electropotential energy $ (U _s - U _A) $

physics energy and its forms idea of energy introduction to work and energy work and energy
    • 10J
    • 10J
    • 21J
    • 2J
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Correct Option: A

Taking the unit of work as Joule and the unit of amount of heat as K cal, the magnitude in Joule for mechanical equivalence of heat is:

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. $1$

  2. $4.2 \times 10^7$

  3. $4.2$

  4. $4.2 \times 10^3$

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Correct Option: D
Explanation:

$1\ kcal=4.2\times1000=4.2\times10^3\ J$


How many joules is equal to one calorie?

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. 1

  2. 0

  3. 2

  4. 3

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Correct Option: A
Explanation:

 1 calorie = 4.2 joules

Define the term calorie. How is it related to joule ?

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. The amount of energy requires to raise the temperature of 1 gram of water by 1° Celsius, 1 Cal = 4.18 J

  2. The amount of energy requires to raise the temperature of 1 gram of water by 1 Kelvin, 4.18 Cal = 1 J

  3. The amount of energy requires to raise the temperature of 1 gram of water by 1 Fahrenheit, 4.18 Cal = 1 J

  4. The amount of energy requires to raise the temperature of 1 gram of ether by 1° Celsius, 1 Cal = 4.18 J

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Correct Option: A
Explanation:
The term calorie can be defined as the energy needed to raise the temperature of 1 gram of water by $ 1$ °C. 
$1 \ cal = 4.18 \ J$

The energy required to accelerate a car from $10:m/s$ to $20:m/s$ is how many times the energy required to accelerate the car from the rest to $10:m/s$:

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. Equal

  2. 4 times

  3. 2 times

  4. 3 times

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Correct Option: D
Explanation:

Energy required to accelerate from $\displaystyle 10:m/s$ to $20:m/s$ $E _{1}=\frac{1}{2}m(400-100)$


Energy  required to accelerate from rest to $\displaystyle 10:m/s$  $E _{2}=\frac{1}{2}m(100-0)$

$\displaystyle \frac{E _{1}}{E _{2}}=\frac{\frac{1}{2}m(300)}{\frac{1}{2}m(100)}=3:times$

Cost of electricity for home use is Rs. 1.50 per unit. This unit is:

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. 1 ampere

  2. 1 volt

  3. 1 joule

  4. 1 kilowatt hour

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Correct Option: D
Explanation:

The electrical unit for the electricity of home is used as kilowatt hour (kWh). Here the cost of 1 kWh electricity is Rs 150.  

The unit $kg m^2s^{-2}$ is associated with:

physics energy and its forms idea of energy introduction to work and energy work and energy

  1. work

  2. kinetic energy

  3. potential energy

  4. all the above

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Correct Option: D
Explanation:

This is unit of energy $ML^2T^{-2}$ (in dimensional form).

All the quantities given in the option are different form of energy ao their units will be same. So the given unit is associated with all.