Please refer to Current Electricity Class 12 Physics Important Questions with solutions provided below. These questions and answers have been provided for Class 12 Physics based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these problem solutions as it will help them to gain more marks in examinations. We have provided Important Questions for Class 12 Physics for all chapters in your book. These Board exam questions have been designed by expert teachers of Standard 12.
Class 12 Physics Important Questions Current Electricity
Case Based Questions :
Read the paragraph given below and choose the correct alternative for questions given after paragraph:
Low-power potentiometers, both slide and rotary, are used to control audio equipment, changing loudness, frequency attenuation, and other characteristics of audio signals. The ‘log pot’, that is, a potentiometer has a resistance of a logarithmic (log) form, is used as the volume control in audio power amplifiers, where it is also called an “audio taper pot”, because the amplitude response of the human ear is approximately logarithmic. It ensures that on a volume control marked 0 to 10, for example, a setting of 5 sounds subjectively half as loud as a setting of 10. There is also an anti-log pot or reverse audio taper which is simply the reverse of a logarithmic potentiometer. It is almost always used in a ganged
configuration with a logarithmic potentiometer, for instance, in an audio balance control.
Question. The material preferred to make wire of potentiometer is:
(a) Copper
(b) Silver
(c) Nichrome
(d) Manganin
Answer
D
Question. At null point, the power of potentiometer is
(a) Zero
(b) Maximum
(c) Minimum
(d) Infinite
Answer
A
Question. The principle of potentiometer is derived from: irrelevant
(a) Wheatstone bridge
(b) Joule’s law of heating
(c) Ohm’s law
(d) Kirchoff’s loop rule
Answer
C
Question. Two cells of emfs 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm. Which of the following is true for this potentiometer?
(a) The battery that runs the potentiometer should have voltage of 7.5 V.
(b) The battery that runs the potentiometer should have a voltage of 15 V and external resistance to be adjusted so that potential drop across the wire slightly exceeds 10 V.
(c) The first 50 cm of wire itself should have a potential drop of 10 V
(d) Potentiometer is usually used to compare resistances not voltages.
Answer
B
