List of practice Questions

A beam of light reflects and refracts at the surface between air and glass. The index of refraction of the glass is \(1.4\). If the refracted and reflected rays are perpendicular to each other, then the angle of incidence in the air is:

A charge \( Q \) is to be divided between two objects. The values of the charges on the objects so that the electrostatic force between them will be maximum is:

In a space having electric field \( \vec{E} = A(x\hat{i} + y\hat{j}) \), the potential at point (10 m, 20 m) is zero. Then the potential at the origin is: (Given \( A = 10 \, \text{Vm}^{-2} \))

Electric potential due to a space is given by: \[ \phi(x, y, z) = \phi_0 \cdot \frac{x_0}{x} \] where \( x_0 = 5\,\text{m}, \phi_0 = 8\,\text{V} \). Find the electric field at the point (10 m, 5 m, 5 m).

A Carnot engine operating between temperatures \( T_H = 600\,K \) and \( T_C = 300\,K \), absorbs \( Q_H = 800 \, \text{J} \) of heat from the source. The mechanical work done per cycle is:

An object of mass 3 kg is tied by a string of negligible mass to a ceiling and held such that the string is taut. The object is released suddenly such that the string remains taut. It’s acceleration when released is (acceleration due to gravity = 10 m s$^{-2}$)

A force $\vec{F} = 4\hat{i} - 15\hat{j}$ N acts on a body resulting in a displacement of $6\hat{i}$. If the body had kinetic energy of 7 joules at the beginning of the displacement, the kinetic energy at the end of the displacement is

Consider a force $F = K x^3$ which acts on a particle at rest. The work done by the force for the displacement of 2 m is ($K = 2 \, \text{N m}^{-3}$)

The centre of mass of a homogeneous semi-circular plate of radius $r$ is located at A as shown in the figure. The distance $OA$ is

The dot product of unit vectors $\hat{n}_1$ and $\hat{n}_2$ that are parallel to $5\hat{i} + 12\hat{j}$ and $3\hat{i} + 4\hat{j}$ respectively is

A sphere rolls down from the top of an inclined plane which makes an angle $30^\circ$ with the edge of a horizontal roof of a house. If the highest and lowest points of the inclined plane are 8.75 m and 3.75 m respectively from the ground then the horizontal distance from the lower edge of the roof at which the sphere hits the ground is (acceleration due to gravity = 10 m s$^{-2}$)

At the moment $t = 0$, a time dependent force $F = at$ (where $a$ is constant equal to 1 N s$^{-1}$) is applied on a body of mass 1 kg resting on a smooth horizontal plane as shown in the figure. If the direction of this force makes an angle $45^\circ$ with the horizontal, then the velocity of the body at the moment it leaves the plane is (acceleration due to gravity = 10 m s$^{-2}$)

The derivative of the function $f(x) = \sin(x^2)$ at $x = \sqrt{\pi}$ is

The integrating factor of the linear differential equation $\frac{dy}{dx} + P(x)y = Q(x)$ is a solution of the differential equation

By multiplying with $e^{\int P dx}$ on both sides of the equation $\frac{dy}{dx} + P(x)y = Q(x)$, the left side of the equation takes the form $\frac{d}{dx} (y f(x))$, then $f(x) =$

Let \( f(x) = \int \frac{e^{3x}}{4 + 8e^{2x} + e^{4x}} \, dx \), and \( g(x) = \int \frac{2\, dx}{e^{3x} + 8e^x + 4e^{-x}} \), then \( f(x) - g(x) = \) ?

If \( a, b, c, d \ne 0 \) and \( \int \frac{at + b}{ct + d} dt = t \), then find \( \int f(x) dx \) where \( f(x) = \frac{ax + b}{cx + d} \)

Evaluate: \( \int_{0}^{4} \frac{x + 2}{\sqrt{4x - x^2}}\, dx \)

Two curves \( y = a^x \) and \( y = b^x \) intersect at some angle \( \alpha \). Find \( \tan \alpha \).

Find the area of the triangle formed by the tangent to the curve \( xy = a^2 \) at \( (x_1, y_1) \) and the coordinate axes.

In the interval \( (7, \infty) \), the function \( f(x) = |x - 5| + 2|x - 7| \) is:

If the line \( ax + by + c = 0 \) is a normal to the curve \( xy = 1 \), then which of the following is true?

Evaluate \( \int \frac{dx}{1 + a \cos x} \), given \( a>|\sec \theta| \)

Evaluate: \[ \lim_{n \to \infty} \sqrt{2} \left[ \frac{ \left(2 + \sqrt{2} \right)^n + \left(2 - \sqrt{2} \right)^n }{ \left(2 + \sqrt{2} \right)^n - \left(2 - \sqrt{2} \right)^n } \right] \]

If \( \frac{d^n y}{dx^n} = y_n \) and \( y = e^{\sqrt{x}} + e^{-\sqrt{x}} \), then find the value of \( 4x y_2 + 2 y_1 \).