MEDIUM
Earn 100

What is the primary reason for deforestation leading to biodiversity loss?

50% studentsanswered this correctly

Important Questions on Laws of Motion

EASY
A body of mass M moving with velocity v explodes into two equal parts. If one part comes to rest and the other part moves with velocity v0; what would be the value of v0?
EASY
Two spherical black bodies have radii r1 and r 2. Their surface temperatures are T1 and T 2. If they radiate same power then r2r1 is
EASY
The potential energy of a system increases if work is done
MEDIUM
A mass M attached to a horizontal spring executes S.H.M. of amplitude A1. When the mass M passes through its mean position, then a smaller mass m is placed over it and both of them move together with amplitude A2. The ratio of A1A2 is
MEDIUM
A block of mass 10 kg is kept on a rough inclined plane as shown in the figure. A force of 3 N is applied on the block. The coefficient of static friction between the plane and the block is 0.6. What should be the minimum value of force P, such that the block does not move downward? (take g=10 m s-2)
Question Image
EASY
A perfect black body is one whose emissive power is
EASY
If wavelengths of maximum intensity of radiations emitted by the sun and the moon are 0.5 x 10-6 m and 10-4 m respectively, the ratio of their temperatures is
EASY
A black body radiates energy at the rate of E Wm-2 at a high temperature T K. When the temperature is reduced to T2 K, the radiant energy is
EASY
In which mode of transmission, the heat waves travel along straight line with the speed of light?
EASY
The earth radiates in the infra-red region of the spectrum. The spectrum is correctly given by
EASY
We consider the radiation emitted by the human body. Which of the following statements is true?
HARD
A spherical black body with a radius of 12 cm radiates 450 W power at 500 K. If the radius were halved, and the temperature doubled, the power radiated in watt would be
EASY
The temperature at which a black body ceases to radiate energy, is
EASY
Two spheres of the same material have radii 1 m and  4 m and temperature 4000 K and 2000 K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is
EASY
An ideal black body, at room temperature, is thrown into a furnance. It is observed that,
EASY
Following graphs show the variation in the intensity of heat radiations by the black body and frequency at a fixed temperature. Choose the correct option.
EASY
A black body is heated from 27°C to 927°C. The ratio of radiation emitted will be,
EASY
A black body at a temperature of 227°C radiates heat at the rate of  20 cal m-2s-1. When its temperature rises to 727°C the rate of heat radiated will be
EASY
Two spheres made of same material have radii in the ratio 2:1. If both the spheres are at same temperature, then what is the ration of heat radiation energy emitted per second by them?
EASY
A metal ball of surface area200 cm2  and temperature 5270C is surrounded by a vessel at 270C. If the emissivity of the metal is 0.4, then the rate of loss of heat from the ball is σ = 5.67 × 1 0 - 8 J / m 2 - s - k 4