Waec Physics 1991 Past Questions and Answers

Question 46:

• WAEC 1991

Using the data in the circuit illustrated above, calculate the value of R

A. 0.02\(\Omega\)
B. 0.05\(\Omega\)
C. 5.00\(\Omega\)
D. 20.00\(\Omega\)
E. 50.00\(\Omega\)

Question 47:

• WAEC 1991

A 90W immersion heater is used to supply energy for 5 minutes. The energy supplied is used to completely melt 160g of a solid at its melting point. Calculate the specific latent heat of the solid.

A. 2.81jg^-1
B. 6.25Jg^-1
C. 8.89Jg^-1
D. 168.75Jg^-1
E. 5333.33Jg^-1

Question 48:

• WAEC 1991

In the circuit above R is a resistor whose resistance increases with increases with increase in temperature L₁ and L₂ are identical lamps. If the temperature of R increases

A. L₁ becomes brighter and L₂ becomes dimmer
B. L₁ becomes brighter and L₂ does not change
C. L₂ becomes dimmer and L₁ does not change
D. L₁ becomes dimmer and L₂ does not change
E. L₁ and L₂ becomes brighter

Question 49:

• WAEC 1991

A house is supplied with a 240V a.c mains. To operate a door bell rated at 8v, a transformer is used if the number of turns in the primary coil of the transformer is 900. calculate the number of turns in the secondary coil of the transformer

A. 30
B. 240
C. 248
D. 450
E. 1248

Question 50:

• WAEC 1991

The diagram above shows a current carrying wire between the poles of a magnet. In which direction would the wire tend to move?

A. Into the paper
B. Out of the paper
C. Towargs the north pole of the magnet
D. Towards the south pole of the magnet
E. Towards the top of the pages