Physics Past Questions and Answers

a proton moving with a speed of 1.0 x 10⁶ms^-1 through a magnetic field of 1.0T experiences a magnetic force of magnitude 8.0 x 10^-14 N. The angle between the proton''s velocity and the field is

A 60Â°
B 90°
C 30Â°
D 45Â°

Question 12:

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

A Increases then decreases
B Increases
C Decreases
D Remains constant

Question 13:

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

A V
B III
C I
D II

Question 14:

The charge carriers in gasses are

A Ions only
B Electrons and ions
C Electrons and holes
D Electrons only

Question 15:

the ray which causes gas molecules to glow is known as

A Cathode ray
B Anode ray
C Molecular ray
D Gamma ray