Current Electricity Class 12 Physics MCQs Pdf
21. An electric heater is connected to the voltage supply. After few seconds, current
gets its steady value then its initial current will be
(a) equal to its steady current
(b) slightly higher than its steady current
(c) slightly less than its steady current
(d) zero
Answer
Answer: b
22. In the series combination of two or more than two resistances
(a) the current through each resistance is same.
(b) the voltage through each resistance is same.
(c) neither current nor voltage through each re-sistance is same.
(d) both current and voltage through each resis¬tance are same.
Answer
Answer: a
23. Combine three resistors 5 Q, 4.5 Q and 3 Q in such a way that the total
resistance of this combination is maximum
(a) 12.5 Q
(b) 13.5 Q
(c) 14.5 Q
(d) 16.5 Q
Answer
Answer: a
24. A cell having an emf E and internal resistance r is connected across a variable
external resistance R. As the resistance R is increased, the plot of potential
difference V across R is given by
Answer
Answer: b
25. In parallel combination of n cells, we obtain
(a) more voltage
(b) more current
(c) less voltage
(d) less current
Answer
Answer: b
26. If n cells each of emf e and internal resistance r are connected in parallel,
then the total emf and internal resistance will be
Answer
Answer: a
27. In a Wheatstone bridge if the battery and galvanometer are interchanged then the
deflection in galvanometer will
(a) change in previous direction
(b) not change
(c) change in opposite direction
(d) none of these.
Answer
Answer: b
28. When a metal conductor connected to left gap of a meter bridge is heated, the
balancing point
(a) shifts towards right
(b) shifts towards left
(c) remains unchanged
(d) remains at zero
Answer
Answer: a
29. In a potentiometer of 10 wires, the balance point is obtained on the
7th wire. To shift the balance point to 9th wire, we should
(a) decrease resistance in the main circuit.
(b) increase resistance in the main circuit.
(c) decrease resistance in series with the cell whose emf is to be measured.
(d) increase resistance in series with the cell whose emf is to be determined.
Answer
Answer: d
30. AB is a wire of potentiometer with the increase in the value of resistance R, the
shift in the balance point J will be
(a) towards B
(b) towards A
(c) remains constant
(d) first towards B then back towards A.
Answer
Answer: a