Question

A wire PQ of length l and area of cross-section A is
connected to a supply of V volt

(where volt meter is connected in parallel with the wire PQ)


If the length of the wire is doubled and its area of
cross-section halved, then the reading of the
ammeter and the voltmeter respectively
(1) Increases, increases
(2) Increases, remains the same
(3) Decreases, remains the same
(4) Remains the same, remains the same

Answer 1

it's 3.AS RESISTANCE INCREASES To 4 times as it's pl/a. So voltmeter is used to measure voltage which would not let current to flow through it. therefore if current increases voltmeter measures more accurate reading. whereas ammeter is used to measure current which decreases as resistance increases

Answer 2

answer is 3 because resistance is directly proportional to v and inversely proportional to I
here resistance will be doubled when length is doubled and area of cross section is halved