The design of the thermostat of an electric iron is based on the
emmision of electrons from metals when heated
increase in size of metals when heated
increase in the density of metals when heated
change in the mass of metals when heated
Correct answer is B
No explanation has been provided for this answer.
Which of the following equations for the efficiency of a machine is correct?
Efficiency = \(\frac{\text{Velocity Ratio}}{\text{Mechanical Advantage}}\) x 100%
Efficiency = \(\frac{input}{output}\) x 100%
Efficiency = \(\frac{\text{load distance}}{\text{effort distance}}\) x 100%
Efficiency = \(\frac{\text{Mechanical Advantage}}{\text{Velocity Ratio}}\) x 100%
Correct answer is D
No explanation has been provided for this answer.
0.8m
4.0m
4.8m
5.6m
Correct answer is C
h = \(\frac{PE}{mg} - \frac{12}{0.25 \times 10} = 4.8m\)
Which of the following devices convert heat energy to electrical energy?
transformer
dynamo
thermocouple
thermostat
Correct answer is C
No explanation has been provided for this answer.
kinetic energy is increasing
potential energy is increasing
potential energy is decreasing
kinetic energy remains constant
Correct answer is B
The Kinetic Energy of a body is energy possessed by a body as a result of its motion. Hence, while in motion the kinetic energy of a body changes into potential energy as it rebounds from the floor