Jamb Physics 1985 Past Questions and Answers

Question 41:

• JAMB 1985

On which of the following does the operation of a moving coil ammeter depend? i. Electromagnetic induction ii. Force on a carrying-current conductor iii. Magnetic effect of an electric current

A. I only
B. Ii only
C. Iii only
D. Ii and iii only
E. I,ii and iii

Question 42:

• JAMB 1985

Which of the following statements is NOT correct?

A. A galvanometer can be converted to an ammeter with a different range by connecting a high resistance in series
B. An electric current always produces a magnetic field
C. Maxwell's screw rule states that if a corkscrew moves inthe direction of the current, the hand turns in the direction of the lines of force
D. Electromagnets are used in electric bells and telephone recievers
E. The lines of force round a straight current carrying conductor are circular

Question 43:

• JAMB 1985

A transformer has a primary coil with 500 turns and a secondary coil with 2500 turns. When the voltage input to the primary coil is 120V, the output is

A. 6000V
B. 600V
C. 240V
D. 60V
E. 24V

Question 44:

• JAMB 1985

Which of the following statements about electrolysis is NOT correct?

A. The substances in solution in the electrolyte become ionized
B. Ions are electrically charged and are attracted towards electrodes when a potential difference is applied
C. Ions may be discharged at the electrodes, forming bubbles or deposits
D. The mass deposited depends upon the length of time for which current flows
E. The mass of gas set free or metal deposited is proportional to the square of the current

Question 45:

• JAMB 1985

Which of the following statements is NOT correct?

A. The average range of distinct vision for a normal eye is from the far distance (infinity) up to about 25cm in front of the eye
B. Longsighted people have difficulty in making the eye lense sufficiently powerful to focus on nearby objects
C. Shortsighted people cannot accommodate distant objects
D. Longsighted people need diverging spectacle lenses
E. A person with long sight has his eye-ball too short and the image of an object is therefore formed behind the retina