JAMB Physics Past Questions & Answers - Page 162

806.

A zinc has a heat capacity of 40 J/K, what is the mass of the zinc, given that the specific heat of zinc is 380 J/kg k

A.

0.11kg

B.

0.12kg

C.

0.13kg

D.

0.14kg

Correct answer is A

Heat capacity (o) = mass (kg) specific heat of a substance (C2)

i.e Q = MC

where Q = 40 J/L, m = ?(380 J/Kgk)

40 = m × 380

m = 0.11kg (Approx)

807.

If a mango fruit dropped at a height of 50 meters. How long does it reach the ground? (take g = 10m/s2)

A.

2 sec

B.

3 sec

C.

4 sec

D.

3.2 sec

Correct answer is D

From S = ut + ½gt2

u = 0ms-1

50 = (0 × t) + ½(10)(t2)

50 = 5.0t2

t2 =50/5

t = √10

t = 3.2sec

808.

What type of electromagnetic radiation can be used to take photographs in the haze?

A.

Radio waves

B.

infrared rays

C.

Visible light

D.

Gamma rays

Correct answer is B

 

Infrared rays are easily detected by special photographic films and it can be used for taking picture in haze

809.

Lodestone is a natural magnet, it points at

A.

N – W when suspended freely

B.

N–S when suspended freely

C.

S – E when suspended freely

D.

S–W when suspended freely

Correct answer is B

 

Lodestone is a natural magnet it points approximate at N – S when suspended freely

810.

Quantities of heat Q can be measured using a container called

A.

Thermometer

B.

Measuring cylinder

C.

Calorimeter

D.

Meter rule

Correct answer is C

 

Calorimeter is an apparatuses used for measuring the heat (Q) generated or absorbed by change of phase (state) or other physical change