List of practice Questions

Given f(x) = esinx+ecosx, The global maximum value of f(x)

An amplitude-modulated wave is represented by cm (t) = 10[1+0.6 sin(1250t)] sin(103 t). Then the modulation index is: 

Which of the following statements is true about LEDs

The average ordinate of y=sin x over [0,\(\pi\)] is

Photodiodes are mostly operated in reverse biased conditions because: 

Heavy water is used to moderate in nuclear reactor because

In a hypothetical Bohr hydrogen atom, if the mass of the electron is double then the energy of the electron in the first orbit is: 

Electromagnetic radiation of intensity 0.6 Wn-2 is falling on a blank surface. The radiation pressure on the surface is: 

At very high frequencies, the current (i) in the given circuit is:

A copper disc of radius 0.1 m rotates about an axis passing through its center and perpendicular to its plane with 10 revolutions per second in a uniform transverse magnetic field of 0.1 T. The emf induced across the radius of the disc is:

Metal detector works on the principle of

If x=sinθ and y=sin kθ, then (1-x2)y2-xy1-αy=0, for α=

If γ is the susceptibility and μr is the relative permeability of a ferromagnetic substance, then

\(\int_{0}^{2\pi}\theta sin^6\theta cos\theta\,d\theta\) is equal to
In the interval (-2\(\pi\),0), the function f(x)=sin(\(\frac{1}{x^3}\)).

It is found that a non-zero current is unable to produce any magnetic field at a particular point. Then the angle between the current element and the position vector of that point with respect to the current element is:

A wire of resistance 2R is stretched such that its length is doubled. Then the increase in its resistance is: 

The value of \(\lim_{n\rightarrow\infty}[(\frac{1}{2.3}+\frac{1}{2^2.3})+(\frac{1}{2^2.3^2}+\frac{1}{2^3.3^2})+.....+(\frac{1}{2^n.3^n}+\frac{1}{2^{n+1}.3^n})]\)
The family of curves y=easin x, where a is an arbitrary constant, is represented by the differential equation

The effective capacitance between points A and B shown in the circuit is: 

If the electrical potential at a point on the surface of a hollow conducting sphere of radius R is V, then the electric potential at a point which is at a distance R/3 from the centre of the sphere is: 

A point source of light is placed at the focus of a concave mirror. Consider only paraxial rays. The shapes of the wavefronts of incident and reflected lights respectively are: 

Two convex lenses of focal lengths 20 cm and 30 cm are placed in contact with each other co-axially. The focal length of the combination is: 

A source and an observer move away from each other with same velocity of 10 m-1 with respect to the ground. If the observer finds the frequency of sound coming from the source as 1980 Hz, then the actual frequency of the source is (speed of sound in air = 340 ms-1)

Among the following statements, the correct statement for a wave is: