The de-Broglie wavelength of an electorn having 80 eV of energy is nearly (1eV = 1.6 x 10−19 J , Mass of the electron = 9 x 10−31K g , planck′s constant = 6.6 x 10−34J − sec
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An electron and a proton have same de-Broglie's wavelength. The kinetic energy of an electron is
A heavy steel ball of mass greater than 1 kg moving with a speed of 2 m sec⁻1 collides head on with a stationary ping-pong ball of mass less than 0.1 gm. The collision is elastic. After the collision the ping-pong ball moves approximately with speed
A particle of mass m at rest decays into two masses m₁ and m₂ with non-zero velocities. The ratio of de-Broglie wavelengths of the masses λ₁/λ₂ is
In a Wheatstone's bridge, all the four arms have equal resistance R. If resistance of the galvanometer arm is also R, then equivalent resistance of the combination is
Consider the two following statements A and B and identify the correct choice given in the answers;
(A) In photovoltaic cells the photoelectric current produced is not proportional to the, intensity of incident light.
(B) In gas filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation.
An inductance L having a resistance R is connected to an alternating source of angular frequency ω. The quality factor (Q) of the inductance is L/R
What is the value of inductance L for which the current is a maximum in series LCR circuit with C = 10 μF and ω = 1000s−1 ?
The displacement current arises when electric field in a region
A doubly ionised He+2 atom travels at right angles to a magnetic field of induction 0.4T at a velocity of 105ms−1 describing a circle of radius r. A proton travelling with same speed in the same direction in the same field will describe a circle of radius
A hollow metal sphere of radius 5cm is charged such that the potential on its surface is 10 volt. The potential at the centre of the sphere is
A body of mass 2 kg is thrown up vertically with kinetic energy of 490 joules. If the acceleration due to gravity is 9.8 m/s2, then the height at which the K.E. of the body becomes half its original value is given by
A light and a heavy body have equal kinetic energy. Which one has a greater momentum ?
The earth radiates in the infra-red region of the spectrum. The spectrum is correctly given by
A 10 Ω electric heater operates on a 110 V line. Calculate the rate at which it develops heat in watts.
In a deflection magnetometer experiment in tan A position, a short-bar magnet placed at 18 cm from the centre of the compass needle produces a deflection of 30º . If another magnet of same length but 16 times pole strength as that of first magnet is placed in tan B position at 36cm, the deflection will be
In a deflection magnetometer experiment the deflections produced separately by two short bar magnets kept at the same distance are 45º and 30º . Then the ratio of the magnetic moments of the two magnets is
A cube is subjected to a uniform volumatric compression. If side of cube decreases by 1%, then its bulk strain is
The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is
A sample of wood decayed to 1/16 of its original value. What is the number of T1/2 ?
A particle execute simple harmonic motion with a frequency f. The frequency with which its kinetic energy oscillates is
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): In a uniform circular motion angle between velocity vector and acceleration vector is always π/2 .
Reason(R): For any type of motion, angle between acceleration and velocity is always π/2 .
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): In an organ pipe the antinode is formed exactly at the open end, but slightly outside.
Reason(R): Vibrations of the air particles in the pipe are not restricted to the open end but occur outside also.
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): It is easier to start a car engine on a warm day than cold day.
Reason(R): Internal energy of the engine is high on a warm day than a cold day .
In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Two identical charged particles enter a uniform magnetic field with speeds v1 and v2 (where v2 > v1) , then they move along circles of radii (r1 > r2) respectively .
Reason(R): The radius of the path is proportional to the momentum of the charged particle.