Physics Past Questions and Answers

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 1622:

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 1623:

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\(\Omega\)

Question 1624:

Two identical charges situated 20cm apart in vacuum repel each other with a force of 1.0N.Calculate the value of each other with a force of 1.0N. Calculate the value of each charge. [(14 \(\pi \varepsilon_o)^{-1}\) = 9 x 10⁹Nm²C^-2]

A 21\(\mu C\)
B 3.6\(\mu C\)
C 4.0\(\mu C\)
D 4.4\(\mu C\)

Question 1625:

In the circuit diagram above, E is a battery of negligible internal resistance. If its emf is 9.0V. Calculate the current in the circuit ``

A 1.8A
B 1.0A
C 0.8A
D 0.3A