If a charged particle (+ q) is projected with certain velocity parallel to the magnetic field, then it will

• trace helical path

• trace circular path

• continue its motion without any change

• come to rest instantly

Optical fibres, though bent in any manner, allows light to pass through. What is the inference that one can draw from it?

• The concept that light travels in straight path is wrong

• Light can flow through the optical fibres

• Light can travel through the fibres because of their ductility

• Light can travel through the fibres due to multiple total internal reflections

Match List-I with List-II

List I (Physical quantity)

1. Distance
2. Amount of material
3. Amount of electrical charge
4. Energy

List II (Unit)

1. Mole
2. Coulomb
3. Light year
4. Watt hour

• (a) - 3, (b) - 1, (c) - 2, (d) - 4

• (a) - 3, (b) - 2, (c) - 1, (d) - 4

• (a) - 4, (b) - 2, (c) - 1, (d) - 3

• (a) - 4, (b) - 1, (c) - 2, (d) - 3

A ray of light when refracted suffers change in velocity. In this context, which one among the following statements is correct?

• Velocity increases as the ray passes from a rarer to a denser medium

• Velocity decreases as the ray passes from a denser to a rarer medium

• Velocity decreases as the ray passes from a rarer to a denser medium

• Change of velocity does not depend on the nature of medium

An object is placed 10 cm in front of a convex lens of focal length 15 cm. 'The image produced will be

• Real and magnified

• Virtual and magnified

• Virtual and reduced in size

• Real and reduced in size

Why is Graphite used in electrolytic cells?

• Graphite is soft and can be easily moulded into electrodes

• Graphite is made of layers of carbon atoms which can slide

• Graphite is inert to most ofthe chemicals and remains intact in electrolytic cells

• Graphite is a good conductor of electricity

A solid is melted and allowed to cool and solidify again. The temperature is measured at equal intervals of time. The graph below shows the change of temperature with time.

The part of the curve that is practically horizontal is due to

• latent heat given away by the liquid

• specific heat given away by the liquid

• thermal capacity changes with time keeping temperature constant

• change in density during transformation

168.

The product of conductivity and resistivity of a conductor

• depends on pressure applied

• depends on current flowing through conductor

• is the same for all conductors

• varies from conductor to conductor

We use CFL to save electrical energy and to provide sufficient light. The full form of CFL is

• Condensed filament light

• Compact filament lamp

• Condensed fluorescent lamp

• Compact fluorescent lamp

When the sun is 30° above the horizon, shadow of one tree is 17 .3 m long. What is the height of this tree?

• 20 m

• 17.30 m

• 10 m

• 1.73 m