Latest Posts

The position-time graph of a particle of mass 4 kg is shoen below. What is the (a) force on the particle for t < 0, t > 4 s, 0 < t < 4 s? (b) impulse at t = 0 and t = 4 s? (Consider one-dimensional motion).

Solution When t＜0, the distance covered by the particle is zero. Therefore, the force on the particle is zero. When... View Article

A bullet of mass 100 g is fired from a gun of mass 20 kg with a velocity of 100ms ⁻¹. Calculate the velocity of recoil of the gun:

Given Mass of bullet =m=100g=100 /1000kg=1/10kg Velocity of bullet, v=100ms-1 Mass of gun, M=20kg Find out We have to determine... View Article

A body is moving along a rough horizontal surface with an initial velocity of 10ms^-1. If the body comes to rest after travelling a distance of 12m, then the coefficient of sliding friction will be

Sliding friction as the resistance created by any two objects when sliding against each other. This friction is also known... View Article

A particle is projected making angle 45º with horizontal having kinetic energy K. The kinetic energy at highest point will be

When a particle is thrown obliquely near the earth’s surface, it moves along a curved path under constant acceleration that... View Article

If 1/(b-a) + 1/(b-c) = (1/a) + (1/c), then a,b,c are in (1) AP (2) GP (3) HP (4) none of these

The correct answer is (3) HP A Harmonic Progression (HP) is defined as a sequence of real numbers which is... View Article

If the ratio of the concentration of electrons to that of holes in a semiconductor is 7/5 and the ratio of currents is 7/4, then what is the ratio of their drift velocities? (a) 5/8 (b) 4/5 (c) 5/4 (d) 4/7

The drift velocity is defined as an average velocity attained by the charged particles (electrons) in a material due to... View Article

Temperatures of two stars are in ratio 3:2. If wavelength of maximum intensity of first body is 4000 Å, what is corresponding wavelength of second body?

Wien’s law or Wien’s displacement law, named after Wilhelm Wien was derived in the year 1893 which states that black body... View Article

ABC is an isosceles triangle in which altitudes BE and CF are drawn to equal sides AC and AB respectively (see Figure). Show that these altitudes are equal.

Given According to the given data (i) BE and CF are altitudes. (ii) AC = AB To prove: We have... View Article

Point (0, -2) lies on y-axis. Is the given statement true or false?

The given statemnet is true Solution a cartesian plane is a two-dimensional coordinate plane, which is formed by the intersection of... View Article

What should be the minimum coefficient of static friction between the plane and the cylinder for the cylinder, for the cylinder not to slip on an inclined plane

Solution Let us assume The friction force as f The normal force acting on the shell as NFor translation motion, −f+Mgsinθ=Ma….(i)[a is... View Article

A particle of mass m moving in the x direction with speed 2v is hit by another particle of mass 2m moving in the y direction with speed v. If the collision is perfectly inelastic, the percentage loss in the energy during the collision is close to:

Initial energy, E1=1/2m(2v)2+12(2m)v2=3mv2Now, by law of cnservation of momentum, 3mV=2√2mv ⇒V=2√2v3Final energy, E2=1/2(3m)V2=4/3mv2Now, E1−E2/E1×100 =56% Check out the video given below to know more... View Article

Find the value of k for which the equation 3x²+2x+k=0 has distinct and real root.

Given, 3x2 + 2x + k = 0 It’s of the form of ax2 + bx + c = 0... View Article

If a certain piece of copper is to be shaped into a conductor of minimum resistance, its length (l) and cross-sectional area (a) shall respectively be (a) l and d (b) 2l , d (c) 1/2 , 2d (d) 2l , d/2

The correct answer is (c) 1/2 , 2d Solution From ohm’s law and also from resistivity we know that As... View Article

Two plane mirrors are inclined at an angle θ. A ray of light is reflected from the first mirror and is then incident on the second mirror from which it is again reflected. What is deviation of incident ray?

A mirror with a flat surface is a plane mirror that reflects light and produces a virtual image without the... View Article

A particle of charge q and mass m moves in a circular orbit of radius r with angular speed ω. The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on 1) ω and q 2) ω, q and m 3) q and m 4) ω and m

The correct answer is 3) q and m Solution A magnetic moment is a quantity that represents the magnetic strength... View Article

If a magnet is suspended at an angle of 30º to the magnetic meridian, the dip needle makes an angle of 45º with the horizontal. The real dip is________

If a magnet is suspended at an angle of 30º to the magnetic meridian, the dip needle makes an angle... View Article

A 2kg box sits on a 3kg box which sits on a 5kg box. The 5kg box rests on a table top. What is the normal force exerted by the 5kg box on the 3kg box?

The normal force is equal to the weight of the body during deceleration. When the body is about fall, depends... View Article

The width of a river is 1km. The velocity of the boat is 5km/hr . The boat covered the width of the river with the shortest will possible in 15 min. Then the velocity of river stream is:

Given Width of river = 3km/h the velocity of the boat =5km/hr Time is taken for shortest path = 15... View Article

If A and B are two sets such that A ⊂ B, then what is A ∪ B?

Union of Sets Definition The union of two sets X and Y is equal to the set of elements that... View Article

n identical light bulbs, each designed to draw P power from a certain voltage supply, are joined in series across that supply. The total power which they will draw is

Electric power is the rate at which work is done or energy is transformed into an electrical circuit. Simply put,... View Article

«
1
…
557
558
559
560
561
…
5,472
»