List of practice Questions

The waves used for line of sight communication and satellite communication are:

If the magnetisation of a material is M and the magnetic field in the material is B, then the magnetic intensity is: ($\mu_0$ = permeability of free space)

If a generator of emf 440 V and internal resistance 400 $\Omega$ is connected to an external resistance of 4000 $\Omega$, then the potential difference across the external resistance is:

If the length and the focal length of its objective of an astronomical telescope are L and 8 respectively, then the focal length of its eyepiece is:

Rain is falling vertically with a speed of $ 36\ \mathrm{m/s} $ and a boy is moving on a bicycle with a speed of $ 20\ \mathrm{m/s} $ towards south. The angle with the vertical towards south with which the boy has to hold an umbrella is

A balloon of mass 'M' is rising up with an acceleration 'a'. In order to triple its acceleration, the fraction of mass to be removed from the balloon is ($ g $ - acceleration due to gravity)

Identify the amide which gives propan-1-amine by Hoffmann bromamide reaction.

Which of the following compounds give salt of an acid and alcohol on heating with concentrated KOH?

What is Z in the given reaction sequence? \[ {(1) } B_2H_6 \longrightarrow X \xrightarrow{PCC} Y \xrightarrow{NH_2OH} Z \] \[ {(2) } H_2O, H_2O_2, OH^- \]

Polyacrylonitrile is used as a substitute for wool in making commercial fibres as acrilan. The structure of it is:

A compound consists of atoms A and B. The atoms of B form hcp lattice. The atoms of A occupy $\frac{1}{3}$ rd of octahedral voids and $\frac{1}{3}$ rd of tetrahedral voids. What is the molecular formula of the compound?

Consider the following statements:
Statement-I: The products formed when diborane burns in air are ${B}_2{O}_3$, ${H}_2$, and ${O}_2$.
Statement-II: Hybridization of boron atom in orthoboric acid is $sp^2$. The correct answer is:

Which of the following is not related to the removal of permanent hardness of water?

At what temperature rms speed of ${SO}_3$ molecules is $3.16 \times 10^2 \, {ms}^{-1}$? (R = 8.314 J K$^{-1}$ mol$^{-1}$)

Observe the following molecules:
${SO}_2, {H}_2{O}, {HgCl}_2, {BeCl}_2, {XeF}_2, {O}_3, {NO}_2, {PbCl}_2$.
The number of molecules with the same geometry as that of ${SnCl}_2$ is:

A spectral line of Lyman series of H-atom has a frequency of $2.466 \times 10^{15} \, {s}^{-1}$. What is the transition responsible for this spectral line? (Rydberg constant $R = 1.096 \times 10^7 \, {m}^{-1}$)

Two diodes with zero resistance in forward bias and infinite resistance in reverse bias are connected to a battery as shown in the circuit. Then the value of current $i$ is:

When an electron beam of energy 10.2 eV is used to excite hydrogen gas, then the possible spectral line is:

A particle is moving with a velocity four times the velocity of an electron. If the de Broglie wavelength of the particle is $1.5 \times 10^{-4}$ times the de Broglie wavelength of the electron, then the mass of the particle is (mass of electron $= 9 \times 10^{-31} \, {kg}$):

The electric field between the plates of a parallel plate capacitor changes at the rate of $4.5 \times 10^{7} \, {V/m/s}$. If the plates of the capacitor are circular with radius 2 cm, then the displacement current inside the capacitor is:

The device constructed based on the laws of electromagnetic induction is:

The magnetic force per unit length acting on a wire carrying a current of $4\sqrt{3}$ A and making an angle of $60^\circ$ with the direction of a uniform magnetic field of 200 mT is:

The magnetic field at a point $ P $ at a distance of 2 cm from a long straight wire of diameter 0.5 mm carrying a current of 1 A is $ B $. If the diameter of the wire is doubled without changing the current, the magnetic field at the same point $ P $ is:

The distance travelled by an electron in time of $3\,{ns}$ when accelerated from rest in an electric field of $0.9 \times 10^4\, {N/C}$ is: \[ {(mass of electron } = 9 \times 10^{-31} { kg, charge } = 1.6 \times 10^{-19} { C)} \]

To decrease the capacitance of a parallel plate capacitor: