OAU Physics 2020/2021 - Model Past Questions

Practice each question, then open it to see the full details.

When impurities are added to semi-conductors, the conductivity of the semi-conductor

A.increases
B.decreases
C.remains constant
D.increases then decreases

The ray which causes gas molecules to glow is known as

A.gamma ray
B.molecular ray
C.cathode ray
D.anode ray

A silicon material doped with an element of a certain group and an n-type semi-conductor is formed. The most likely group of the element is

A.I
B.II
C.Ill
D.V

A cell of internal resistance r is connected to an external resistor R. The condition for maximum power transfer is

A.R < r
B.R = 2r
C.R = r
D.R > r

Which of the following materials is a conductor?

A.Sodium.
B.Glass.
C.Plastic.
D.Wax

Which of the following can conduct electricity owing to the presence of free mobile electrons?

A.Germanium
B.Silicon
C.Grapefruit
D.Copper

The resultant of two forces 12N and 5N is 13N. What is the angle between the two forces?

A.0°
B.45°
C.90°
D.180°

An electric device is rated 2000W, 250V. Calculate the maximum current it can take.

A.9A
B.8A
C.7A
D.6A

A car battery rated 45AH is charged with a charger whose rating is 2.5A. How long will it take to charge the battery fully?

A.25hrs
B.20hrs
C.18hrs
D.10 hrs

When a ship sails from salt water into fresh water, the fraction of its volume above the water surface will

A.remain the same
B.increase
C.decrease
D.increase then decrease

What charge is stored in a 0.1F capacitorwhen a 10V supply is connected across it?

A.1C
B.5C
C.4C
D.2C

A simple pendulum has a period of 17.0s. When the length is shortened by 1.5m. its period is 8.5s. Calculate the original length of the pendulum.

A.1.55m
B.2.0m
C.3.0m
D.4.0m