JAMB Physics Past Questions & Answers - Page 122

606.

The value of T in the figure above is

A.

10.0N

B.

11.8N

C.

20.0N

D.

40.0N

Correct answer is D

No explanation has been provided for this answer.

607.

In the above fig, PQ and R are vectors, which of the following options, gives a correct relationship between the vectors?

A.

P = Q + R

B.

P = Q - R

C.

P = R - Q

D.

P + Q + R = O

Correct answer is A

Addition of vectors:

P = Q + R 

608.

In the curve above, PQRST represents an alternating voltage of frequency 50Hz. The time interval between points P and R on the graph is

A.

25s

B.

1/50s

C.

1/100s

D.

1/200s

Correct answer is C

No explanation has been provided for this answer.

609.

In the circuit diagram above, calculate the current in the 12 Ω resistor if the cell has an emf of 12V and an internal resistance of 1Ω

A.

0.8A

B.

1.0A

C.

1.6A

D.

2.4A

Correct answer is D

\(E = I(R + r)\)

\(I = \frac{E}{R + r}\)

\(\frac{1}{R} = \frac{1}{12} + \frac{1}{6} = \frac{1}{4}\)

\(R = 4\Omega\)

\(I = \frac{12}{1 + 4} = \frac{12}{5}\)

= 2.4A

610.

In the fig above, XY is of length 1m, The value of R at balance point Z is

A.

3.0Ω

B.

13.3Ω

C.

15.0Ω

D.

30.0Ω

Correct answer is D

At null deflection, p.d across R = p.d across xz

p.d across 20Ω = p.d across zy 

\(\frac{R}{20}\) = \(\frac{60}{40}\)

R = 30Ω