Question

For question numbers 15 and 16, two statements are given- one labeled Assertion (A) and the

other labeled Reason (R). Select the correct answer to these questions from the codes (a), (b),

(c) and (d) as given below:

a) Both A and R are true, and R is correct explanation of the assertion.

b) Both A and R are true, but R is not the correct explanation of the assertion.

c) A is true, but R is false.

d) A is false, but R is true.

(i) Assertion (A): Three lamps connected in series will create more heat than three lamps

connected in parallel.

Reason (R): Series combination results in larger resistance.

(ii) Assertion (A): Two copper wire of different length will have the same resistance.

Reason (R): Resistivity does not depend on the length of the conductor.
​

Answer 1

Explanation:

(I) Both A and R are true and R is the correct explanation of R

This is because the formula for resistance in series circuit is R=R1+ R2 + R3 and so on

while formula for parallel is

1/R= 1/R1 + 1/R2 and so on.So naturally,series will have more resistance. And more resistance means more heat because more electrical energy would be converted to heat energy while passing through a conductor with higher resisatnce.

(II)A is false and R is true

resistance is directly proportional to length of conductor but resistivity doesn't depend on length of the conductor .Two conductors of different length cannot and will not have the same resistance