Which of th following transitions in a hydrogen atom emits the photon of highest frequency?
A nucleus with Z = 92 emits the following in a sequence: α,β⁻,β⁻,α,α,α,α,α,β⁻,β⁻,α,β⁺,β⁺,α. The atomic no. of the resulting nuclues is
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Uniform wire 16 Ω resistance is made in the form of a square. Two opposite corners of the square are connected by a wire of resistance of 16 Ω . The effective resistance between the other two opposite corners is
Three similar cells, each of e.m.f. 2V and internal resistance r Ω send the same current through an external resistance of 2 Ω, when connected in series or in parallel. The strength of the current flowing through the external resistance is
Uncertainty in position of the electron is of the order of de-Broglie wavelength. Making use of Heisenberg's uncertainty principle, it will be found that uncertainty in velocity ν is of the order of
If momentum of a particle is doubled, then its de-Broglie's wavelength will
Radio wave diffract around building although light waves do not. The reason is that radio waves:
Five equal capacitors connected in series have a resultant capacitance of 4 μF. The total energy stored in these, when these are connected in parallel and charged to 400V is
A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F capacitor. The decrease in the energy of the system will be
Taking that earth revolves round the sun in a circular orbit of radius 15 x 1010 m, with a time period of 1 year, the time taken by another planet, which is a distance of 540 x 1010 m, to revolve round the sun in circular orbit once, will be
The energy spectrum of a black body exhibits a maximum around a wavelength λ₀. The temperature of a black body is now changed such that the energy is maximum around a wavelength 0.75 λ₀. The power radiated by the black body will now increase by a factor of
A liquid cools down from 70ºC to 60ºC in 5 minutes. The time taken to cool it from 60ºC to 50ºC will be
If a particle covers half the circle of radius R with constant speed, then
A wire of length L metre, carrying a current I ampere is bent in the form of a circle. its magnitude of magnetic moment will be
A particle is moving eastwards with a velocity of 5 m − s⁻1. In 10 s, the velocity changes to 5 m − s⁻1 northwards. The average acceleration in this time is
A particle is viberating in a simple harmonic motion with an amplitude of 4 cm. At what displacement from the equilibrium position, is its energy half potential and kinetic ?
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): Due to opposition offered by self-inductance, work is done by external agent in establishing current in circuit. This work done is stored as potential energy.
Reason(R): Self-inductance of a coil depends on the geometry of coils and medium.
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): Both heat energy and charge are carried by the free electrons in pure metals.
Reason(R) : For pure metals, the electrical conductivity σ is directly related to the thermal conductivity K.
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): Costly wrist watches and other instruments are enclosed in a soft-iron case to protect it from external field.
Reason(R): Iron-case is used as magnetic screening or shielding.
If 'S' is stress and 'Y' is Young's modulus of material of a wire, then the energy stored in the wire per unit volume is
The density of ice is 9.0 g/c.c. and that of sea water is 1.1 g/c.c. An ice berg of volume V is floating in sea water. The fraction of ice berg above water level is
A light ray passed through an equilateral prism. If the angles of incidence and emergence are 45°45° and 55°55°respectively, the angle of deviation is
A constant torque of 314 N-m is exerted on a pivoted wheel. If angular acceleration of wheel is 4π rad-s⁻², then the moment of inertia of the wheel is
Two bodies M and N of equal masses are suspended from two separate massless springsof force constants K₁ and K₂ respectively. If the two bodies oscillate vertically such that their maximum velocities are eqaul, the ratio of the amplitude of M to that of N is
A stretched string is in unison with a tuning fork of frequency 392 Hz. If the length of the string is decreased by 2%, the number of beats heard per second is
During the adiabatic process, the pressure of gas is found to be proportional to the cube of its absolute temperature. The ratio CP/CV for gas is
A given system undergoes a change, in which work done by a system equal to decrease in its internal energy. The system must have undergone an
For the constructive interference the path difference between the two interfering waves must be equal to