Question 4346:

• NECO 2000

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 4347:

• NECO 2000

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 4348:

• NECO 2000

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 4349:

• NECO 2000

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 4350:

• NECO 2000

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