An object placed at a distance 30 cm in front of a lens produces clear inverted image at a distance 60 cm from the lens. If the object is placed at 60 cm from the lens, then it produces a clear inverted image at a distance of …………… from the lens.

1. 20 cm
2. 30 cm
3. 60 cm
4. 90 cm

Assertion (A) : Quartz prism is used to study ultraviolet spectrum.

Reason (R) : Quartz does not absorb ultraviolet radiations.

1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true and (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false and (R) is true.

According to the NEW international convention, what is the colour coding for the live, neutral and earth wires in household circuits?

1. Live – red, Neutral – black, Earth – green
2. Live – green, Neutral – yellow, Earth – black
3. Live – brown, Neutral – blue, Earth – yellow
4. Live – red, Neutral – blue, Earth – yellow

An alloy constantan has resistivity 5 x 10^-7 Ω m at 25°C. If the temperature of this alloy is increased to 50°C then its resistivity will be:

1. 2.5 x 10^-7 Ω m
2. 5 x 10^-7 Ω m
3. 10 x 10^-6 Ω m
4. 20 x 10^-6 Ω m