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, the magnetic field at its centre becomes:
(a) Double
(b) Half
(c) Four times
(d) One fourth
Concept: Magnetic Force
Name a material which is used in making control rods in a nuclear reactor.
Concept: Atomic Masses and Composition of Nucleus
Write one balanced equation to show Emission of `beta^-` (i.e. a negative beta particle)
Concept: Atomic Masses and Composition of Nucleus
An emf of 2V is induced in a coil when the current in it is changed from 0A to 10A in 0·40 sec. Find the coefficient of self-inductance of the coil.
Concept: Electromagnetic Induction
Explain the term hysteresis
Concept: Magnetic Force
Obtain an expression for magnetic flux density B at the centre of a circular coil of radius R, having N turns and carrying a current I
Concept: Magnetic Force
With the help of a suitable example and an equation, explain the term pair production.
Concept: Atomic Masses and Composition of Nucleus
Calculate the net emf across A and B shown in Figure 1 below :
Concept: Electric Current
Obtain an expression for electric potential ‘V’ at a point in an end-on position i.e. axial position of the electric dipole.
Concept: Electric Potential
Derive the law of reflection using Huygen’s Wave Theory.
Concept: Huygens Principle
(i) Draw a labelled circuit diagram of a half wave rectifier and give its output waveform.
(ii) Draw a symbol for NOR gate and write its its truth table.
Concept: Materials, Devices and Simple Circuits
(i) Draw a neat circuit diagram to study the input and output characteristics of a common emitter transistor.
(ii) Draw the symbol for AND gate and write its truth table.
Concept: Materials, Devices and Simple Circuits
With what type of source of light are cylindrical wave fronts associated?
Concept: Huygens Principle
A converging lens of focal length 40 cm is kept in contact with a diverging lens of focal length 30 cm. Find the focal length of the combination .
Concept: Reflection of Light by Spherical Mirrors
How can the spherical aberration produced by a lens be minimized?
Concept: Reflection of Light by Spherical Mirrors
A metallic wire having a length of 2 m and weight of 4 x 10-3 N is found to remain at rest in a uniform and transverse magnetic field of 2 x 10-4 T. Current flowing through the wire is:
Concept: Electric Current
Two thin lenses having optical powers of -10D and+ 6D are placed in contact with each other. The focal length of the combination is:
Concept: Reflection of Light by Spherical Mirrors
The total energy of an electron in the ground state of the hydrogen atom is -13·6 eV. Its total energy, when a hydrogen atom is in the first excited state, is:
Concept: Alpha-particle Scattering and Rutherford’S Nuclear Model of Atom
Write the expression for the Lorentz force F in vector form.
Concept: Magnetic Force
A coil has a self-inductance of 0·05 Henry. Find the magnitude of the emf induced in it when the current flowing through it is changing at the rate of 100 As-1.
Concept: Electromagnetic Induction