List of practice Questions

Two equal capacitors are first connected in series and then in parallel. The ratio of the equivalent capacities in the two cases will be :

A cube of side 'a' has point charges +Q located at each of its vertices except at the origin where the charge is -Q. The electric field at the centre of cube is : 

If an emitter current is changed by 4 mA, the collector current changes by 3.5 mA. The value of β will be :

In the given figure, energy levels of H-atom are shown. Transitions A ($n=\infty \to 1$), B ($n=4 \to 2$), C ($n=4 \to 3$) represent : 

Statement I : Two photons having equal linear momenta have equal wavelengths. Statement II : If the wavelength of photon is decreased, momentum and energy will also decrease.
The focal length $f$ is related to the radius of curvature $r$ of the spherical convex mirror by :
In a YDSE, width of one slit is three times the other. Amplitude is proportional to slit-width. Find the ratio $I_{max}/I_{min}$.
The coefficient of static friction between a wooden block of mass 0.5 kg and a vertical rough wall is 0.2. The magnitude of horizontal force that should be applied on the block to keep it adhere to the wall will be _________ N. [ g = 10 ms⁻² ]
An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be ________ Lumens.
A ball with a speed of 9 m/s collides with another identical ball at rest. After the collision, the direction of each ball makes an angle of 30° with the original direction. The ratio of velocities of the balls after collision is x : y, where x is _________
A hydraulic press can lift 100 kg when a mass 'm' is placed on the smaller piston. It can lift _________ kg when the diameter of the larger piston is increased by 4 times and that of the smaller piston is decreased by 4 times keeping the same mass 'm' on the smaller piston.
An inclined plane is bent in such a way that the vertical cross-section is given by $y = x^2 / 4$. If the upper surface is rough with $\mu = 0.5$, the maximum height in cm at which a stationary block will not slip downward is _________ cm.
A resonance circuit having inductance and resistance $2 \times 10^{-4}$ H and $6.28$ Ω respectively oscillates at 10 MHz frequency. The value of quality factor of this resonator is __________.
An audio signal $v_m = 20 \sin 2\pi(1500t)$ amplitude modulates a carrier $v_c = 80 \sin 2\pi(100,000t)$. The value of percent modulation is ________

In connection with the circuit drawn below (assuming a Zener diode circuit with $V_z=10V$, $R_s=500\Omega$, $R_L=2k\Omega$, $V_{in}=15V$), the value of current flowing through 2 kΩ resistor is _________ × 10⁻⁴ A. 

An electromagnetic wave of frequency 5 GHz, is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are 2. Its velocity in this medium is ________ × 10⁷ m/s.
A common transistor radio set requires 12 V (D.C.). The D.C. source is constructed using a transformer and a rectifier circuit operated at 220 V (A.C.). The number of turns of secondary coil are 24, then the number of turns of primary are _________. (Assume ideal transformer)
Which of the following are isostructural pairs ? (Note: Based on typical JEE pairs like $SO_4^{2-}$ and $BF_4^-$ or $NH_3$ and $PH_3$)

In Freundlich adsorption isotherm, slope of AB line is : 

Which of the following ore is concentrated using group 1 cyanide salt ?

(A) \( \mathrm{HOCl + H_2O_2 \rightarrow H_3O^+ + Cl^- + O_2} \)  |  
(B) \( \mathrm{I_2 + H_2O_2 + 2OH^- \rightarrow 2I^- + 2H_2O + O_2} \). 
Choose the correct option. 

\( \mathrm{Al_2O_3} \) was leached with alkali to get \( X \). The solution of \( X \), on passing the gas \( Y \), forms \( Z \). \( X, Y \) and \( Z \) respectively are :
The electrode potential of \( \mathrm{M^{2+}/M} \) of 3d-series elements shows positive value for :
The major components in “Gun Metal” are :
The gas released during anaerobic degradation of vegetation may lead to :