WAEC Past Questions and Answers - Page 3287

16,431.

The resistivity, \(\mathit{P}\), of a material of length l, cross-sectional area A, resistance R, is given by the equation

A.

\(\mathit{P} = \frac{RA}{l}\)

B.

\(\mathit{P} = \frac{l}{RA}\)

C.

\(\mathit{P} = \frac{Rl}{A}\)

D.

\(\mathit{P} = \frac{R}{Al}\)

Correct answer is A

 resistivity P  is directly proportional to the product of resistance and cross-sectional area and inversely proportional to the length of the wire

16,432.

An ammeter with a full scale deflection of 10mA has an internal resistance 0.5\(\Omega\). calculate the resistance of the shunt required to adapt it to read up to 3A

A.

0.0167\(\Omega\)

B.

0.0130\(\Omega\)

C.

0.0250\(\Omega\)

D.

0.1000\(\Omega\)

Correct answer is A

\(R_2 = \frac{I_1R_1}{I_2} = \frac{0.01 \times 5}{2.99}\)

= 0.0167

16,433.

The unit of capacitance is

A.

farad

B.

coulomb

C.

henry

D.

ohms

Correct answer is A

No explanation has been provided for this answer.

16,434.

Which of the following substances does not conduct electricity?

A.

graphite

B.

glass

C.

sulphuric acid

D.

table salt solution

Correct answer is B

No explanation has been provided for this answer.

16,435.

When the pointed end of an uncharged optical pin is brought near the cap cf a positively charged electroscope, it is observed that the gold

A.

collapse slowly

B.

vibrate

C.

are not affected

D.

diverge rapidly

Correct answer is A

No explanation has been provided for this answer.