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At sunrise or at sunset the sun appears to be reddish while at midday it looks white. Explain.

The scattering of light by tiny particles with regard to the wavelength of the incident light is known as Rayleigh scattering. Light intensity is... View Article

A ball is dropped from the top of a tower of height 100m. Simultaneously, another ball was thrown upward from the bottom of the tower with a speed of 25m/s (g=10ms2 ). These two balls would cross each other after a time: A) 1 second B) 2 second C) 3 second D) 4 second

Here we can see a tower is there of 100m and a ball from 100m height is falling under gravity which is 10m/s2 and another ball is... View Article

If a ball is thrown vertically upwards with 40m/s its velocity after two seconds will be:-

The acceleration of the body will be due to the earth's gravitational force, therefore the acceleration will be –g (the negative sign indicates... View Article

The mass of the earth is 81 times the mass of the Moon and the distance between the earth and the Moon is 60 times the radius of earth. If R is the radius of the earth, then the distance between the Moon and the point on the line joining the Moon and the earth where the gravitational force becomes zero is

Consider that the moon's mass is M. As a result, the earth's mass is 81M. The radius of the earth is R once more. As a result, r=60R is the... View Article

A current flows in a conductor from east to west. The direction of the magnetic field at a point above the conductor is: A. towards east B. towards west C. towards north D. towards south

Answer: (c) Towards north The 3D orientation of the axis is represented by the right hand thumb rule. However, in our scenario, we have the... View Article

A circular coil carrying a current I has radius R and number of turns N . If all the three, i.e., the current I, radius R and number of turns N are doubled, then magnetic field at its centre becomes

When current I flows in a circular coil with radius R and number of turns N, we first apply the Biot-Savart law to calculate the relationship... View Article

A train of mass M is moving on a circular track of radius R with a constant speed v. The length of the train is half of the perimeter of the track. Find the linear momentum of the train.

Around the Y-axis, the train is symmetrical. A and B are two symmetrical positions on the Y-axis that correspond to two points in the train's... View Article

The gravitational force causes (A) Tides (B) None of them (C) Motion of moon (D) Both (a) and (c)

Answer: (D) Both (a) and (c) The moon travels in a round orbit around the earth. Despite the fact that the orbit is not round, it is... View Article

If energy(E), velocity (V) and force (F) be taken as fundamental quantity, then what are the dimension of mass ?

The quantities that are independent of other quantities are called fundamental quantities. The units that are used to measure these fundamental... View Article

Two rods Aand Bof different materials are welded together as shown in the figure. Their thermal conductivities are K1 and K2. What is the thermal conductivity of the composite rod?

In fact, it plays a critical part in conduction heat transfer, although we tend to address the conductivity mode of heat transfer without knowing... View Article

Which of the following is not a characteristic of a waves, (a) amplitude (b) frequency (c) wavelength and (d) none

Answer: (d) none The wavelength of a longitudinal wave is the distance between two successive points in the same phase, such as two... View Article

A gun of mass M fires a bullet of mass m with maximum speed v. Given that m

The kinetic energy formula is given by, Kinetic energy =1/2 × mass × (velocity)2 Using conservation of linear momentum m1v1 + m2v2 = 0 m1 =... View Article

Write the formula of maximum velocity to avoid skidding of a vehicle moving on a level circular path.

The gravitational attraction force is measured in milligrams (mg). Frictional force (f) - acting parallel to the slope of the road between the... View Article

A jet airplane travelling at a speed of 500 km/h ejects its products of combustion at a speed of 1500 km/h relative to the jet plane. The speed of the latter with respect to an observer on the ground is:

Let's start by defining what the word "relative motion" means. The motion of a body relative to another body (referred to as an observer) is the... View Article

An object weighs 10N at the north pole of the earth. In a geostationary satellite distance 7R from the centre of the earth (of radius R). What are the true weight and the apparent weight?

Acceleration due to gravity at a height h from the surface , g ′ =g[1+h/R ]−2 For radius of orbit =7R⟹h=6R mg ′ =mg[1+ 6R/R ]−2 mg ′... View Article

Derive an expression for acceleration due to gravity at a depth ‘d’ below the earth’s earth surface.

Consider M as the mass of the earth, R be the radius of the earth gd be gravitational acceleration at depth ′ d ′ from the earth surface g be... View Article

How will the image formed by a convex lens be affected if the central portion of lens is wrapped in black paper ?

answer: The full image will be formed, but it is less bright As a result of a huge number of rays from the object forming an image. As a... View Article

How many Faradays of electricity are required to deposit 10 g of calcium from molten calcium chloride using inert electrodes? (molar mass of calcium = 40 g mol −1)

The equation is written as Ca2+ +2e− → Ca Number of moles of Ca= 10g /40g/mol =0.25mol 1 mole Ca requires =2 moles of electrons =2... View Article

The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5V lies in the : A. infrared region B. X-ray region C. Ultraviolet region D. Visible region

We are given the value W=6.2eV for the work function of a photosensitive material's surface. V=5V is the stopping potential for a specific... View Article

A proton, deutron and an α-particle enter a magnetic field perpendicular to field with same velocity. What is the ratio of the radii of circular paths?

Each of the three particles has a charge. The proton has a positive charge of +e, the deuteron has a positive charge of +e, and the alpha... View Article

M	T	W	T	F	S	S
					1	2
3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	19	20	21	22	23
24	25	26	27	28	29	30
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