Correct Answer - Option 1 : Linear

__Concept:__

In thermocouple instruments, the deflection is directly proportional to the square of the current. i.e. θ ∝ I2

In moving iron instruments, the deflection is directly proportional to the square of the current. i.e. θ ∝ I2

In hotwire instruments, the deflection is directly proportional to the square of the current. i.e. θ ∝ I2

In moving-coil instruments, the deflection is directly proportional to the current. i.e. θ ∝ I

__Application:__

Moving coil instruments have a uniform or linear scale.