# 1994 - WAEC Physics Past Questions & Answers - page 1

1
which of the following is a scalar quantity?
A
Tension
B
Weight
C
Impulse
D
Upthrust
CORRECT OPTION: e
2
In which of the following simple machines is the effort applied between the load and the fulcrum?
A
Scissors
B
Pliers
C
Wheel barrow
D
Sugar tongs
CORRECT OPTION: d
3

The ice and steam points on a mercury in glass thermometer are found to be 90mm apart. What temperature is recorded in degree Celsius when the length of the mercury thread is 33.6mm above the ice point mark?

A
33.6°C
B
35.0°C
C
37.3°C
D
52.7°C
CORRECT OPTION: c

$$\frac{x - 0}{100 - 0} = \frac{33.6 - 0}{90 - 0}$$

$$\frac{x}{100} = \frac{33.6}{90}$$

$$90x = 3360 \implies x = \frac{3360}{90}$$

= 37.3°C

4
A gas occupies a certain volume at 27°C. At what temperature will its volume be three times the original volume assuming that its pressure remains constant?
A
81°C
B
162°C
C
354°C
D
627°C
CORRECT OPTION: d
$$\frac{V_{1}}{T_{1}}$$ = $$\frac{V_{2}}{T_{2}}$$ x $$\frac{V_{1}}{27+273}$$ = $$\frac{3V_{1}}{T_{2}}$$ , $$T_{2}$$= 900K; T=627°C
5
When two objects P and Q are supplied with the same quantity of heat,the temperature change in P is observed to be twice that in Q. If the masses of P and Q are the same,calculate the ratio of the specific heat capacities of P and Q
A
1:1
B
1:3
C
1:4
D
1:2
CORRECT OPTION: d
$$MC_{p}\ \times 2\theta^2\ = mc\theta\ \times \theta$$ ; $$\frac{C_{p}}{CQ}$$ = $$\frac{m}{2mo}$$
6
The instrument used in the measurement of atmospheric pressure is?
A
Hydrometer
B
Ratemeter
C
Barometer
D
Photometer
CORRECT OPTION: c
7
A tap supplies water at 30°C while another supplies at 86°C. If a man wishes to bath with water at 44°C, calculate the ratio of mass of hot water to that of cold water required
A
1:3
B
3:1
C
3:7
D
7:3
CORRECT OPTION: a
$$M_Hc\theta_{H} = M_cc\theta_c$$
$$M_h(86-44) = M_c(44-30)$$ thus giving 1:3
8
A steam trap is a component of apparatus used in determining the specific latent heat of vaporization of steam. In the steady state, the steam trap
A
stores the steam for future use
B
prevents the steam from escaping
C
ensures that only dry steam gets into the calorimeter
D
allows condensed steam to go into the calorimeter
CORRECT OPTION: c
9
A hygrometer is an instrument used to measure
A
Dew point
B
Temperature
C
Relative density
D
Relative humidity
CORRECT OPTION: d
10
The image of an object placed at the center of the curvature of a concave mirror is
A
Inverted and magnified
B
at the principal focus
C
real and diminshed
D
Erect and virtual
CORRECT OPTION: e
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