Jamb Physics 1991 Past Questions and Answers

Question 36:

• JAMB 1991

An equipment whose power is 1500W and resistance is 375 ohms would draw a current of

A. 0.10A
B. 2.00A
C. 4.00A
D. 77.5A

Question 37:

• JAMB 1991

To convert an alternating current dynamo into a direct current dynamo, the

A. Number of turns in the coil is increased
B. Strength of the field magnet is increased
C. Slip rings are replaced with a split ring commutator
D. Coil is wound on a soft iron armature

Question 38:

• JAMB 1991

If a current carrying coil is mounted on a metal frame, the back e.m.f. induced in the coil causes

A. Inductance
B. Eddy currents
C. Elecro-magnetism
D. Dipole moment

Question 39:

• JAMB 1991

The electrochemical equivalent of platinum is 5.0 x 10^-7kgC^-1 to plate-out 1.0kg of platinum, a current of 100A must be passed through an appropriate vessel for

A. 5.6 hours
B. 56 hours
C. 1.4 x 10^{4 hours}
D. 2.0 x 10^{4 hours}

Question 40:

• JAMB 1991

which of the following statements are TRUE of isotopes? i. isotopes of an element have the same chemical properties because they have the same number of electrons. ii. isotopes of elements are normally separated using physical properties. iii. isotopes of an element have the same number of protons in their nuclei.

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