Anita used a single movable pulley to lift a bucket of water from a well. She lubricates the pulley.

Which of the following statements is true regarding the performance of the pulley used?

1. Mechanical Advantage decreases and efficiency increases.
2. Velocity Ratio increases and efficiency decreases.
3. Mechanical Advantage remains unchanged and efficiency increases.
4. Velocity Ratio remains unchanged and efficiency increases.

Inside the prism, during the dispersion of white light, compared to blue, red light

1. slows down less and refracts more
2. slows down more and refracts less
3. slows down more and refracts more
4. slows down less and refracts less

A convex lens with a focal length of 12 cm has an object at a distance of 20 cm in front of the lens. A blurred image is obtained on the screen placed at a distance of 23 cm in front of the lens. In order to obtain a clear image, the screen has to be moved:

1. towards the lens.
2. away from the lens.
3. to a position very far away from the lens.
4. either towards or away from the lens.

Assertion (A) : Soldiers avoid firing at a target in foggy weather conditions.

Reason (R) : In foggy weather, light gets scattered by tiny water droplets, reducing visibility.

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