Waec Physics 2021 Past Questions and Answers

Question 21:

• WAEC 2021

A metallic sphere is heated from 27°C to 200°C Without change of state. Which of the following changes would have resulted from the heating?

A. No changes occur in its volume and density
B. Its volume increases and its density increases
C. Its volume increases and its density decrease
D. Its volume increases without a change in density

Question 22:

• WAEC 2021

The acceleration of a moving object can be determined from the?

A. Slope of its distance-time graph.
B. Area under its distance-time graph.
C. Slope of its velocity-time graph.
D. Area under its velocity-time graph

Question 23:

• WAEC 2021

A student wishes to measure the potential difference across a resistor,R. She has a galvanometer,G and some connecting wires.
What else does she need?

A. High value resistor connected in parallel with G
B. . low value resistor connected in parallel with G low value
C. Resistor connected in series with G
D. High value resistor connected in series with G.

Question 24:

• WAEC 2021

The handle of a screw jack is 35 cm long and pitch of the screw is 0.5 cm. What force must be applied at the end of the handle to lift a load of 2000N, if the efficiency of the jack is 30% [π = 22/7]?

A. 152.0N
B. 132.0N
C. 15.2N
D. 440.0N

Question 25:

• WAEC 2021

The inductive reactance in a circuit of frequency 100Hz is 1ohms. Calculate the inductance of the inductor[π = 3.14]

A. 2.00 x 10\(_{-3}\)H
B. 1.59 x 10\(_{-3}\)H
C. 1.09 x 10\(_{-3}\)H
D. 6.28x 10\(_{-3}\)H