Current Electricity Charging Discharging Of Capacitors Question 11
Question: Assertion : Leclanche cell is used, when constant supply of electric current is not required. Reason : The e.m.f. of a Leclanche cell falls, if it is used continuously.
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: A
Solution:
The e.m.f. of a Leclanche cell falls, because of the partial polarisation due to accumulation of hydrogen gas. In case, Leclanche cell is used in experiment, where current is drawn after short breaks, then during each break, hydrogen gas escapes and $ Mn _{2}O _{3} $ converts into $ MnO _{2} $ by taking oxygen from the atmosphere. As a result, the cell regains its original e.m.f.