Question: The sound of explosion in a distant star is not heart from the Earth because
1. The frequency of sound produced is below 10 Hz
2. The frequency of sound produced is above 100 Hz
3. There is no continuous medium from the star to Earth
4. The distance of the star is so large that sound intensity falls below the audible range
Answer: 3
Question: In a ‘dynamo’,
1. Electrical energy is converted to mechanical energy
2. Electrical energy is converted to magnetic energy
3. Mechanical energy is converted to electrical energy
4. Mechanical energy is converted to heat energy
Answer: 3
Question: If light enters an equilateral glass prism (n = 1.40) with an angle of incidence of 45 degree, what is the angle of refraction as the beam emerges from the prism? Note that an equilateral triangle has three 60° angles.
1. 67.2°
2. 52.4°
3. 43.5°
4. 60°
Answer: 2
Question: When a beam of light (wavelength = 450 nm),originally travelling in air, enters a piece of glass (index of refraction 1/50), what will happen to its frequency?
1. It gets reduced to 1/3 of its original value
2. It increases by a factor of 1.50
3. It gets unaffected
4. It gets increased by a factor of 3
Answer: 3
Question: When a current carrying conductor is placed above a magnetic needle, what is the maximum deflection that can be produced?
1. 45°
2. 90°
3. 180°
4. 360°
Answer: 2
Question: If a charge of 15.0 C flows through a wire and the amount of electrical energy converted into heat is 1.5 J, what is the potential difference across the ends of the wire?
1. 0.5 V
2. 2.65 V
3. 0.1 V
4. 10 V
Answer: 3
Question: A ray of light hits a plane mirror at 60° from the normal. What is the angle between the reflected ray and the surface of the mirror?
1. 30° from normal
2. 90° from mirror
3. 90° from normal
4. 30° from mirror
Answer: 4
Question: If the potential difference across an electric bulb is 4.6 V and the current flowing through it is 0.25A, what is the resistance of the bulb?
1. 1.15 ohm
2. 18.4 ohm
3. 0.1 ohm
4. 0.625 ohm
Answer: 2
Question: On the Mohs scale, graphite (a principal constituent of pencil “lead”) has a hardness of –
1. 1.5
2. 2.2-2.5
3. 3.2-3.5
4. 5.1
Answer: 1
Question: Faraday’s Law is associated with –
1. Electrolysis
2. Reaction of gases
3. Pressure of gases
4. Temperature and pressure
Answer: 1
Question: At high altitudes it is difficult to cook eggs or vegetables properly because of –
1. High boiling point of water and low atmospheric pressure
2. Low boiling point of water and low atmospheric pressure
3. Low value of acceleration due to gravity
4. High atmospheric pressure and low boiling point of water
Answer: 2
Question: A temperature of 176°F is equal to –
1. 80°C
2. 85°C
3. 75°C
4. 90°C
Answer: 1
Question: In a fuel cell driven vehicle, the energy is obtained from the combustion of –
1. Methane
2. Hydrogen
3. LPG
4. CNG
Answer: 2
Question: Which of the following is used as a material for making protective windows in space probes?
1. Steel
2. Graphite
3. Tungsten
4. Diamond
Answer: 4
Question: No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be –
1. either plane or convex
2. plane only
3. concave
4. convex only
Answer: 2