Question 521:

• JAMB 1988

The fig above shows two waveforms X and Y. If the frequency of X is 30Hz what is the frequency of Y

A. 12Hz
B. 19Hz
C. 60Hz
D. 75Hz

Question 522:

• JAMB 1988

In the fig above, what is the angle of reflection of the ray of light at mirror M?

A. \( 90^{\circ} \)
B. \( 60^{\circ} \)
C. \( 45^{\circ} \)
D. \( 30^{\circ} \)

Question 523:

• JAMB 1988

E,F and G are yellow, red and cyan transparent light filters respectively. The color of a white opaque object when viewed through the arrangement of the filters above is

A. Yellow
B. Red
C. Black
D. Blue

Question 524:

• JAMB 1988

The wire X in the figure above is at right angles to the plane of the paper and carries a current into the paper. at which of the points labelled 1-4, will the magnetic flux density due to this current be in the same direction as that of the horizontal component of earth's magnetic field

A. 1
B. 2
C. 3
D. 4

Question 525:

• JAMB 1988

In the circuit diagram above, the ammeter reads a current of 3A when R is 5 ohms and 6A when R is 6 ohms,the value of the unknown resistance X is

A. 1
B. 2
C. 3
D. 4