The symbol of SI unit of inductance is H. It stands for:

• Holm

• Halogen

• Henry

• Hertz

In a vacuum, a five-rupee coin, a feather of a sparrow bird and a mango are dropped simultaneously from the same height. The time taken by them to reach the bottom is t₁ t₂ and t₃ respectively. In this situation, we will observe that:

• t₁  > t₂ > t₃

• t₁  > t₃ > t₂

• t₃  > t₁ > t₂

• t₁  = t₂ = t₃

Electron emission from a metallic surface by application of light is known as:

• Thermionic emission

• Photoelectric emissior

• High field emission

• Autoelectronic emission

How long does light take to reach the Earth from the Sun?

• About 4 minutes

• About 8 minutes

• About 24 minutes

• About 24 hours

Radioactivity is measured by:

• GM Counter

• Polarimeter

• Calorimeter

• Colorimeter

The mirrors used as rear-view mirrors in vehicles are:

• Concave

• Convex

• Cylindrical

• Plane

Which one ofthe following waves is used for detecting forgery in currency notes?

• Ultraviolet waves

• Infrared waves

• Radio waves

• Microwaves

The majority charge carriers in a p-type semiconductor are:

• free electrons

• conduction electrons

• ions

• holes

79.

Concave mirror is used in headlights of vehicles, because it:

• focuses light from the bulb onto nearby vehicles

• sends parallel rays

• fits well into the shape of the headlight

• is cheaper than other mirrors

If some object is weighed when submerged in water, what will happen to its weight compared to its weight in air?

• Increase

• Decrease

• Remain exactly the same

• Increase or decrease cannot be predicted