Physics Past Questions and Answers

A piece of stone weights 180 N in air and 150 N in a beaker containing 160 N of methylated spirit. What is the up thrust exerted on the stone?

A 50N
B 40N
C 30N
D 20N
E 10N

Question 27:

The half-life of a radioactive substance is 2 seconds. Calculate the decay constant.

A 2.890 s^-1
B 1 .445 s^-1
C 0.576 s^-1
D 0.347s^-1
E 0.152 s^-1

Question 28:

Which of the following is used in a nuclear reactor to slow down fast moving neutrons?

A Graphite rods
B Carbon dioxide gas
C Liquid sodium metal
D Concrete shield
E Boron rods

Question 29:

When electrical power is transmitted over long distances, the voltage is stepped up so that

A The resistance of the wire may be increased proportionately to the potential difference
B The time of transmissions between the generating and the receiving stations may be reduced
C There is increased current to produce brighter lights.
D The rate of electrical consumption is increased.
E The energy waste may be minimised as the current is lowered.

Question 30:

A gas occupies a certain volume at 27°C. At what temperature will its volume be twice times the original volume assuming that its pressure remains constant?

A 54°C
B 108°C
C 150°C
D 327°C
E 600°C