Jamb Physics 1998 Past Questions and Answers

Question 41:

• JAMB 1998

A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in the primary coil.

A. 0.625A
B. 1.600A
C. 2.500A
D. 6.250A

Question 42:

• JAMB 1998

The electrochemical equivalent of a metal is 1.3 x 10^-7kgC^-1. The mass of the metal which 2.0 x 10⁴C of electricity will deposit from a suitable electrolyte is

A. 6.5 x 10^-2kg
B. 2.6 x 10^-2kg
C. 6.5 x 10^-3kg
D. 2.6 x 10^-3kg

Question 43:

• JAMB 1998

In a nuclear fusion experiment, the loss of mass amounts to 1.0 x 10^-6kg. The amount of energy obtained from the fusion is

A. 3.0 x 10^-4J
B. 3.0 x 10^-1J
C. 9.0 x 10⁴J
D. 9.0 x 10¹⁰J

Question 44:

• JAMB 1998

In photoelectric effect, electrons will leave the metal surface when illuminated by light of appropriate frequency if the photon energy is

A. Greater than the work function
B. Less than the work function
C. Equal to the work function
D. Equal to the maximium kinetic energy of the electron

Question 45:

• JAMB 1998

A body on the ground is acted on by a force of 10N at a point P as shown in the fig above. What force is needed to stop the body from moving eastwards

A. 5N in the direction of east
B. 5N in the diretion of west
C. 5V3N in the direction of west
D. 10N in the southwest direction