A moment of couple has a tendency to rotate the body in an anticlockwise direction. Then the moment of couple is taken as :

1. positive
2. negative
3. maximum
4. zero

For burning of coal in a thermoelectric station, the energy conversion taking place is :

1. chemical to heat to mechanical
2. chemical to heat to mechanical to electrical
3. chemical to heat to light
4. heat to chemical to mechanical

The adjacent diagram shows the movable block of a block and tackle system with effort in a convenient direction. From the diagram we can conclude that the number of pulleys used in the fixed block are …………… .

1. 1
2. 3
3. 2
4. 4

White light is dispersed by a prism. Inside the prism, compared to the blue light, the 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