List of practice Questions

An elastic string of unstretched length L and force constant k is stretched by a small length x. It is further stretched by another small length y. The work done in the second stretching is
A body is thrown vertically upwards from A, the top of a tower, and reaches the ground in time t₁. If it is thrown vertically downwards from A with the same speed, it reaches the ground in time t₂. If it is allowed to fall freely from A, then the time taken to reach the ground is
A conducting square loop is placed in a magnetic field B with its plane perpendicular to the field. The sides of the loop start shrinking at a constant rate α. The induced emf in the loop at the instant when its side is a is
The beam of light has three wavelengths 4144AA, 4972AA, 6216AA with a total intensity of 3.6×10⁻3W/m² equally distributed among the three wavelengths. The beam falls normally on a clean metallic surface of work function 2.3eV. Assuming no loss by reflection and that each photon ejects one photoelectron, calculate the number of photoelectrons liberated in 2s.
A solid sphere of radius R has a charge Q distributed in its volume with a charge density ρ = krᵃ, where k and a are constants and r is the distance from centre. If the electric field at r = (R)/(2) is (1)/(8) times that at r = R, the value of a is
A charged particle moving in a uniform magnetic field loses 4% of its kinetic energy. The radius of curvature of its path changes by
Calculate the wavelength of light used in an interference experiment from the following data: Fringe width = 0.03cm. Distance between the slits and eyepiece through which the interference pattern is observed is 1m. Distance between the images of the virtual source when a convex lens of focal length 16cm is used at a distance of 80cm from the eyepiece is 0.8cm.
The displacement of a particle is given at time t, by: x = Asin(-2ω t) + Bsin² ω t Then,
An artificial satellite is moving in a circular orbit around the earth with a speed equal to half the magnitude of the escape velocity from the earth. The height h of the satellite above the earth’s surface is (Take radius of earth as Rₑ):
Two tuning forks with natural frequencies 340 Hz each move relative to a stationary observer. One fork moves away from the observer, while the other moves towards the observer at the same speed. The observer hears beats of frequency 3 Hz. Find the speed of the tuning forks.
Expressed Sequence Tags (ESTs) refers to
In the dicot root the vascular cambium originates from :-
Select the correct option.
How does steroid hormone influence the cellular activities?
Purines found both in DNA and RNA are ;
All the components of the nodal tissue are autoexcitable. Why does the SA node act as the normal pacemakar?
If a circle of radius $R$ passes through the origin $O$ and intersects the coordinate axes at $A$ and $B$, then the locus of the foot of perpendicular from $O$ on $AB$ is :
Potential energy of a body of mass $1\, kg$ free to move along X-axis is given by $U(x) = \left( \frac{x^2}{2} - x \right) J .$ If the total mechanical energy of the body is $2\, J$. then the maximum speed of the body is (Assume only conservative force acts on the body)
Identify $Z$ in the following sequence of reactions. $\ce{ C_2 H_4 Br_2 ->[(i) Alc.KOH][(ii) NaNH_2] X ->[Red\, hot][Fe \,tube\, 873 K] Y ->[(CH_3CO)_2 O/\Delta][Anhyd. AlCl_3] Z}$
If only $\frac{1}{51}^{th}$ ot the main current is to be passed through a galvanometer then the shunt required is $R_1$ and if only $\frac{1}{11}^{th}$ of the main voltage is to be developed across the galvanometer, then the resistance required is $R_2$. Then $\frac{R_2}{R_1} =$
The walls of a closed cubical box of edge $60\, cm$ are made of material of thickness $1\, mm$ and thermal conductivity $4 \times 10^{-4} \; cal \; s^{-1} \; cm^{-1} {^{\circ}C^{-1}}$. The interior of the box is maintained $1000 \; {^{\circ}C}$ above the outside temperature by a heater placed inside the box and connected across $400\, V\, DC$ supply. The resistance of the heater is
In which of the following the election gain enthalpy of elements is correctly arranged?
If the kinetic energy of $O_2$ gas is $4.0 \,kJ \; mol^{-1}$ . its RMS speed in $cm \; s^{-1}$ is
At $T( K )$, copper (atomic mass $=63.5\, u$ ) has fcc unit cell structure with edge length of $x \mathring {A}$. What is the approximate density of $Cu$ in $g \,cm ^{-3}$ at that temperature? $\left(N_{A}=6.0 \times 10^{23} mol ^{-1}\right)$
The number of moles of solute present in the solutions of $I, II$ and $III$ is respectively I. $500 \,mL$ of $0.2\, M\, NaOH$ II. $200 \,mL$ of $0.1 \,N \,H _{2} SO _{4}$ II. $6 g$ of urea in $1 \,kg$ of water