The magnitude of the electric field due to a point charge object at a distance of $$4.0 \mathrm{~m}$$ is $$9 \frac{\math

A point $$P$$ lies at a distance $$x$$ from the mid point of an electric dipole on its axis. The electric potential at p

A current of 0.8 A flows in a conductor of $$40 \Omega$$ for 1 minute. The heat produced in the conductor will be

A cell of emf $$E$$ is connected across an external resistance $$R$$. When current '$$I$$' is drawn from the cell, the p

Beams of electrons and protons move parallel to each other in the same direction. They

A long straight wire of radius '$$a$$' carries a steady current $$I$$. The current is uniformly distributed across its a

$$\vec{E}$$ and $$\vec{B}$$ represent the electric and the magnetic field of an electro- magnetic wave respectively. The

A ray of monochromatic light propagating in air, is incident on the surface of water. Which of the following will be the

A beam of light travels from air into a medium. Its speed and wavelength in the medium are $$1.5 \times 10^8\mathrm{ms}^

Which one of the following metals does not exhibit emission of electrons from its surface when irradiated by visible lig

A hydrogen atom makes a transition from $$n=5$$ to $$n=1$$ orbit. The wavelength of photon emitted is $$\lambda$$. The w

The curve of binding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This im

In an extrinsic semiconductor, the number density of holes is $$4 \times 10^{20} \mathrm{~m}^{-3}$$. If the number densi

Pieces of copper and of silicon are initially at room temperature. Both are heated to temperature T. The conductivity of

The formation of depletion region in a $$p$$-$$n$$ junction diode is due to

Assertion (A) : Diamagnetic substances exhibit magnetism. Reason (R) : Diamagnetic materials do not have permanent magne

Assertion (A) : Work done in moving a charge around a closed path, in an electric field is always zero. Reason (R) : Ele

Assertion (A) : In Young's double slit experiment all fringes are of equal width. Reason (R) : The fringe width depends

Briefly explain why and how a galvanometer is converted into an ammeter.

(a) How are infrared waves produced? Why are these waves referred to as heat waves? Give any two uses of infrared waves.

In the given figure the radius of curvature of curved face in the plano-convex and the plano-concave lens is $$15 \mathr

What happens to the interference pattern when two coherent sources are (a) infinitely close, and (b) far apart from each

(a) What is meant by ionisation energy? Write its value for hydrogen atom. OR (b) Define the term, mass defect. How is i

Draw energy band diagram for an $$n$$-type and $$p$$-type semiconductor at $$\mathrm{T}>0 \mathrm{~K}$$.

Answer the following giving reasons: (i) A $$p$$-$$n$$ junction diode is damaged by a strong current. (ii) Impurities ar

(a) Two charged conducting spheres of radii $$a$$ and $$b$$ are connected to each other by a wire. Find the ratio of the

Define current density and relaxation time. Derive an expression for resistivity of a conductor in terms of number densi

A series CR circuit with $$R=200 \Omega$$ and $$C=(50 / \pi)$$ $$\mu \mathrm{F}$$ is connected across an ac source of pe

Define critical angle for a given pair of media and total internal reflection. Obtain the relation between the critical

(a) (i) Distinguish between nuclear fission and fusion giving an example of each. (ii) Explain the release of energy in

(a) (i) Use Gauss' law to obtain an expression for the electric field due to an infinitely long thin straight wire with

(a) (i) Define coefficient of self-induction. Obtain an expression for self-inductance of a long solenoid of length $$l$

(a) (i) State Huygen's principle. With the help of a diagram, show how a plane wave is reflected from a surface. Hence,

(a) Consider the experimental set up shown in the figure. This jumping ring experiment is an outstanding demonstration o

(a) Figure shows the variation of photoelectric current measured in a photo cell circuit as a function of the potential