Physics (Ch3.1-3.2)

Question 1

What is the formula of power?

Answer 1

P(W)=Q(J)/T(s)

Question 2

What is the unit of power?

Answer 2

Watt(W)

Question 3

Why are joules not used to measure energy transfered in daily life? And what is used?

Answer 3

It is because joules are a very small amount of energy. Kilowatt-hour (kW h) is used instead.

Question 4

What is used to calculate the cost of electrical energy?

Answer 4

Kilowatt-hour

Question 5

Write down the equation of 1kW h.

Answer 5

kW h=(1000 J)(3600 s)

Question 6

What instruments can we use to measure electrical energy supplied to an electrical appliance?

Answer 6

Joulemeter or a kilowatt-hour meter

Question 7

What is the difference of joulemeter and kilowatt-hour meter?

Answer 7

Joulemeter measures the elcetrical energy from a low-voltage power supply while kilowatt-hour meter measures that supplied by the mains.

Question 8

Q is_____ to _T

Answer 8

directly proportional

Question 9

What is the formula for heat capacity?

Answer 9

C=Q/_T

Question 10

What is the unit of heat capacity?

Answer 10

J-1 *C-1

Question 11

The heat capacity of a body is the energy needed to raise the temperture of that ____ by 1 *C.

Answer 11

Body

Question 12

Q is ____ to m.

Answer 12

directly proportional

Question 13

The specific heat capacity of a substance is the energy needed to raise the temperature of ______ by 1 *C

Answer 13

1 kg of the substance

Question 14

The heat capacity describes the thermal property of an ______ while the specific heat capacity describes the thermal property of a _____

Answer 14

object
substance

Question 15

What is the formula of c?

Answer 15

c=Q/m_T

Question 16

What is the unit of specific heat capacity?

Answer 16

kg-1 *C-1