Electro Magnetic Induction And Alternating Currents Question 301
Question: Assertion : The quantity L/R possesses dimensions of time. Reason : To reduce the rate of increases of current through a solenoid should increase the time constant (L/R). [AIIMS 2002]
Options:
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: B
Solution:
The relation of induced emf is $ e=\frac{Ldi}{dt} $ and current i is given by $ i=\frac{e}{R}=\frac{1}{R}.\frac{L.di}{dt} $
Þ $ \frac{di}{dt}=i\frac{R}{L}=\frac{i}{L/R} $ . In order to decreases the rate of increase of current through solenoid. We have to increase the time constant $ \frac{L}{R}. $
