Given below are two statements: Statement I: If the number of turns in the coil of a moving-coil galvanometer is doubled, then the current sensitivity becomes double. Statement II: Increasing current sensitivity of a moving-coil galvanometer only by increasing the number of turns in the coil will also increase its voltage sensitivity in the same ratio. Choose the correct answer.
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Question

Given below are two statements: Statement I: If the number of turns in the coil of a moving-coil galvanometer is doubled, then the current sensitivity becomes double. Statement II: Increasing current sensitivity of a moving-coil galvanometer only by increasing the number of turns in the coil will also increase its voltage sensitivity in the same ratio. Choose the correct answer.

Options

G1 Physics · Accepted Answer

Current sensitivity of a moving-coil galvanometer is θ/I = NBA/k So current sensitivity is directly proportional to the number of turns N. If N is doubled, current sensitivity doubles. Statement I is true. Voltage sensitivity is θ/V = NBA/(kR) When the number of turns is increased using the same wire, the coil resistance R also increases approximately in the same ratio. Therefore N/R remains nearly unchanged and voltage sensitivity does not double. Hence Statement I is true but Statement II is…