Unit - 5.1 Light And General Terms Used In Understanding Light — PHYSICS STD 6 — Question

Write a short note on the theory of magnetism.

Across
3. The force of friction caused due to fluids
4. Type of friction acting between two bodies at rest
5. ‘type of friction which occurs when applied force overcomes static friction
6. A special body design to enable minimum drage
Down
1. type of force which depends upon the roughness of a surface
2. An effect of friction

The output energy of a real life machine is always less than the input energy. Give two reasons for this deficiency.

The length of a school compound is 450 m and breadth is 145 m. Find the area of compound in (a) m2 (b) hectares.

In a lever, the fulcrum is at one end at a distance of 30 cm from the load and effort is at the other end at a distance of 90 cm from the load. Find :
(a) the length of load arm,
(b) the length of effort arm, and
(c) the mechanical advantage of the lever.

Explain the wheel-and-axle arrangement in brief. How does the handle of a bicycle work for this arrangement?

What is a magnet ? Differentiate between natural and artificial magnets.

Draw a neat labelled diagram showing a pulley being used to lift a load. How are load and effort related in an ideal situation?

What is a pinhole camera? Draw a neat and labelled diagram to show the formation of an image of a lighted candle by it.

State two differences between an umbra and a penumbra.