NCERT Exemplar Solutions for Class 12 Physics Chapter 7 – Alternating Current are available here. In this article, you will get solutions from question number 7.1 to question number 7.7. These are basically multiple choice questions with single correct answers (or MCQ I).
These questions can be asked in CBSE Class 12 Physics board exams & other competitive exams like NEET, WBJEE, JEE Main, UPSEE etc.
NCERT Exemplar Solutions for CBSE Class 12 Physics, Chapter 7 (from question number 7.1 to 7.7) are given below:
Solution 7.1: (b)
An alternating current generator has an internal resistance Rg and an internal reactance Xg. It is used to supply power to a passive load consisting of a resistance Rg and a reactance XL. For maximum power to be delivered from the generator to the load, the value of XL is equal to
Solution 7.2: (c)
In order to deliver maximum power the generator to the load, the total reactance must be equal to zero, i.e., XL + Xg = 0 Þ XL = ‒ Xg.
Solution 7.3: (c)
To reduce the resonant frequency in an L-C-R series circuit with a generator
(a) the generator frequency should be reduced
(b) another capacitor should be added in parallel to the first
(c) the iron core of the inductor should be removed
(d) dielectric in the capacitor should be removed
Solution 7.4: (b)
Which of the following combinations should be selected for better tuning of an L-C-R circuit used for communication?
(a) R = 20W, L = 1.5H, C = 35mF
(b) R = 25W, L = 2.5H, C = 45mF
(c) R = 15W, L = 3.5H, C = 30 mF
(d) R = 25W, L = 1.5H, C = 45mF
Solution 7.5: (c)
An inductor of reactance 1W and a resistor of 2W are connected in series to the terminals of a 6V (rms) AC source. The power dissipated in the circuit is
Solution 7.6: (c)