JAMB Physics Past Questions & Answers - Page 79

391.

Which of the following obeys Ohm's law?

A.

all metals

B.

diode only

C.

all electrolytes

D.

glass

Correct answer is A

No explanation has been provided for this answer.

392.

Shadows and eclipses result from the

A.

refraction of light

B.

reflection of light

C.

defraction of light

D.

rectilinear propagation of light

Correct answer is D

No explanation has been provided for this answer.

393.

The electrochemical equivalent of silver is 0.0012g/C. If 36.0g of silver is to be deposited by electrolysis on a surface by passing a steady current for 5mins, the current must be?

A.

6000A

B.

100A

C.

10A

D.

1A

Correct answer is B

Given Data: Mass of Ag = 36.0g,

Z which is electrochemical equivalent of Ag = 0.0012coulomb

 t = 5mins →  5 * 60 = 300secs.

Using M =Z * I * t

make I the subject of the formula
I = \(\frac{M}{Z * t}\)  → \(\frac{36}{0.0012 * 300}\)

Current (I) =  100A

394.

The amount of heat needed to raise the temperature of 10kg of Copper by 1K is its

A.

specific heat capacity

B.

latent heat

C.

heat capacity

D.

internal energy

Correct answer is C

The heat capacity of a defined system is the amount of heat (usually expressed in calories, kilocalories, or joules) needed to raise the system's temperature by one degree (usually expressed in Celsius or Kelvin).

395.

What type of reaction is represented by the following scheme?
\(_{1} ^{2} X\) + \(_{1} ^{2} Y\)  -----> \(_{2} ^{3} Z\) + \(_{0} ^{1} n\) + energy

A.

fusion reaction

B.

fission reaction

C.

Chain reaction

D.

radioactive decay

Correct answer is A

No explanation has been provided for this answer.