Waec Physics 2014 Past Questions and Answers

Question 36:

• WAEC 2014

In an ac circuit when the supply voltage frequency is equal to the resonant frequency, the current

A. Leads the supply voltge by 90^o
B. Lags behind the supply voltage by 90^o
C. Leads the supply voltage by 45^o
D. Is in phase with the supply voltage

Question 37:

• WAEC 2014

The energy stored in a simple cell is

A. Electrical
B. Nuclear
C. Thermal
D. Chemical

Question 38:

• WAEC 2014

Which of the following conditions occur at resonance in a series RLC circuit? i. Impedance equal resistance ii. Current is maximum iii. Reactance are maximum iv. Current and voltage are 90^o out of phase

A. I and ii only
B. I and ii only
C. I, ii and iii only
D. I, ii, iii and iv

Question 39:

• WAEC 2014

An electric motor converts

A. Electrical energy to mechanical energy
B. Mechanical energy to electrical energy
C. Mechanical energy to chemical energy
D. Electrical energy to thermal energy

Question 40:

• WAEC 2014

A 15 \(\mu F\) capacitor is connected to a 240V, 50Hz ac. source. Calculate the reactance of the capacitance [\(\pi = 3.142\)]

A. 16\(\Omega\)
B. 68\(\Omega\)
C. 106\(\Omega\)
D. 212\(\Omega\)