A circuit has a resistance of 12 Ω and an impedance of 15 Ω. The power factor of the circuit will be
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A 10 μ F capacitor and a 20 μ F capacitor are connected in series across 200 V supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together and no external voltage is applied. What is the potential difference across each capacitor?
The kinetic energy of an electron gets tripled, then the de Broglie wavelength associated with it changes by a factor
A shell initially at rest explodes into two pieces of equal mass, then the two pieces will
A uniform resistance wire of length L and diameter d has a resistance R. Another wire of same material has length 4 L and diameter 2 d, the resistance will be
If we express the energy of a photon in KeV and the wavelength in angstroms, then energy of a photon can be calculated from the relation
Who indirectly determined the mass of the electron by measuring the charge of the electron ?
A metallic rod of length l is placed normal to the magnetic field B and revolved in a circular path about one of the ends with angular speed ω. The potential difference across the ends will be
What will be the phase difference between virtual voltage and virtual current, when the current in the circuit is wattless ?
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 ?
An electric dipole consists of two opposite charges of magnitude q seperated by 2a. When the dipole is placed in uniform electric field E, to have minimum potential energy, then dipole moment p makes which the following angle with E
Two spherical conductors A and B having equal radii and carrying equal charges on them, repel each other with a force F, when kept apart at some distance. A third spherical conductor C having same radius as that of A, but uncharged, is brought in contact with A, then brought in contact with B and finally removed away from both. The new force of repulsion between the conductors A and B is
If the linear momentum is increased by 50%, the kinetic energy will increase by
Radiation emitted by a surface is directly proportional to
An electric lamp is marked 60 W, 220 V. The cost of kilo watt hour of electricity is Rs 1.25. The cost of using this lamp on 220 V for 8 hours is
When 2 ampere current is passed through a tangent galvanometer, it gives a deflection of 30º. For 60º deflection, the current must be
The temperature above which a ferromagnetic material become a paramagnetic material is called
The ratio of tangential stress to the shearing strain is called
The time periode of simple pendulum measured inside a stationary lift is found to be T. If the lift starts acclerating upwards with an acceleration g/3, the time periode is
When the bob of a simple pendulum, held in hand is subjected to and fro motion at hill, then the oscillations of the bob will be
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): The centre of mass of an extended object is that point on the object where the resultant of all the external forces acting on the body acts.
Reason(R) : An object under the effect of several external forces moves as if it were a particle placed at its centre of mass and all forces transferred to the point.
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): Pressure in a bubble (σ) in an atmosphere of pressure P0 is where r is the radius.
Reason(R): is the excess pressure due to two surfaces exposed to the atmosphere.
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):When a slow neutron goes sufficient close to a U235 nucleus, energy is liberated.
Reason(R):Process of nuclear fusion takes place.
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): Magnetic field due to circular coil is maximum at the centre and decreases as we move away from the centre on the axis of loop.
Reason(R): Magnetic field on the axis of a circular loop is given by .