Physics Questions and Answers
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.
V
III
I
II
Correct answer is A
Silicon is a tetra valent (4 valent) element, and in order to produce an n type semi-conductor, it has to be dropped with a penta valent (5valent)element, that, that is element in group five (v)
When impurities are added to semi-conductors, the conductivity of the semi-conductor
increases then decreases
increases
decreases
remains constant
Correct answer is B
When impurities are added to semi conductor , the semi conductor is said to be doped, and increases the conductivity of the semi-conductor.
60°
90°
30°
45°
Correct answer is C
The force acting on moving charge in magnetic field is given by: F=q VBSin θ
sin θ =F=(8.0x10)-14/1.6x10-19x1.0x106x1.0 = (8.0x10)14/16 x 1013
(8.0x 10)-14/16x10-14
=0.5000
∴ θ= sin-1 0.5000
=30°
250days
150days
300days
200days
Correct answer is A
Since 1/32, is the fraction left of any radioactive material after 5half lives, that is:
1/32= (1/2)5. Thus if a half life is 50 days, 5 half lives will be 50 x 5= 250 days
In an a.c circuit that contains only a capacitor, the voltage lags behind the current by
180°
90°
60°
30°
Correct answer is B
In a purely capacity circuit, voltage lags behind current by 90°, or current leads voltage by 90°