Question: Which one among the following statements is correct?
1. Concave mirrors are used as reflectors
2. Convex mirrors are used by doctors to examine oral cavity
3. Convex mirrors are used as reflectors
4. Convex mirrors should be used as shaving
Answer: 1
Question: Which one among the following is the major cause of blurring and unsharp images of objects observed through very large telescope at the extreme limit of magnification?
1. Air turbulence of earth’s atmosphere
2. Poor optical polish achievable on large mirrors
3. Poor tracking capacities of telescopes
4. Varying density of air in the Earth’s atmosphere
Answer: 1
Question: The material used for electric fuse is an alloy of tin and lead. This alloy should have:
1. high specific resistance and low melting point.
2. low specific resistance and high melting point.
3. low specific resistance and low melting point.
4. high specific resistance resistance and high melting point
Answer: 1
Question: Light travels slower in glass than in air because:
1. refractive index of air is less than that of glass.
2. refractive index of air is greater than that of glass.
3. density of glass is less than that of air
4. density of glass is greater than that of air.
Answer: 1
Question: A Jet engine works on the principle of Conservation of:
1. linear momentum
2. angular momentum
3. energy
4. mass
Answer: 1
Question: A spherical air bubble is embedded in a piece of glass. For a ray of light passing through the bubble, it behaves like a :
1. converging lens
2. diverging lens
3. piano-converging lens
4. piano-diverging lens
Answer: 2
Question: In a pressure cooker cooking is faster because the increase in vapour pressure:
1. increase the boiling point.
2. increase the specific heat.
3. decrease the specific heat.
4. decrease the boiling point.
Answer: 1
Question: Magnets attract magnetic substances such as iron, nickel, cobalt etc. They can also repel:
1. paramagnetic substances
2. ferromagnetic substances
3. diamagnetic substances
4. non-magnetic substances
Answer: 3
Question: Which of the statements about glass are correct?
1. Glass is a super-cooled liquid having infinite viscosity
2. Violet coloured glass is obtained by adding MnO2
3. Glass is a man-made silicate
4. Glass is a crystalline substance
Select the correct answer using the code given below:
1. 1, 2 and 3
2. 1, 2 and 4
3. 2, 3 and 4
4. 1 and 3 only
Answer: 1