List of practice Questions

The resistance of a wire is $2.5 \Omega$ at a temperature $373 K$. If the temperature coefficient of resistance of the material of the wire is $3.6 \times 10^{-3} K^{-1}$, its resistance at a temperature $273 K$ is nearly:

When two identical resistors are connected in series to an ideal cell, the current through each resistor is $ 2 $ A. If the resistors are connected in parallel to the cell, the current through each resistor is?

An electron falling freely under the influence of gravity enters a uniform magnetic field directed towards south. The electron is initially deflected towards?

A short magnet placed in a uniform magnetic field making an angle with the field experiences a torque. If the angle made by the magnet with the field is changed from $30^\circ$ to $45^\circ$, the torque on the magnet?

Observe the following reactions:

The correct answer is:

The efficiency of a bulb of power $ 60 $ W is $ 16\% $. The peak value of the electric field produced by the electromagnetic radiation from the bulb at a distance of $ 2 $ m from the bulb is? \[ \left(\frac{1}{4\pi \epsilon_0} = 9 \times 10^9 \text{ Nm}^2\text{C}^{-2} \right) \]

Two statements are given below:
I. Shaving soaps contain sodium carbonate
II. Laundry soaps contain sodium rosinates
The correct answer is:

The work function of a photosensitive metal surface is $ 1.1 $ eV. Two light beams of energies $ 1.5 $ eV and $ 2 $ eV incident on the metal surface. The ratio of the maximum velocities of the emitted photoelectrons is?

Which of the following are present in DNA?

The ground state energy of a hydrogen atom is $ -13.6 $ eV. The potential energy of the electron in the first excited state of hydrogen is?

After the decay of a single $ \beta^- $ particle, the parent and daughter nuclei are?

Which of the following is vulcanised rubber?

The sum of coordination number and oxidation number of the metal M in the complex \[ [M({en})_2(C_2O_4)] \quad {(en = ethylenediamine)} \]

Which of the following reducing agents liberates hydrogen from dilute acid?

What are X and Y respectively in the following reactions? \[ {Cu} + {HNO}_3 \, ({dilute}) \rightarrow {Cu(NO}_3)_2 + {H}_2{O} + X \] \[ {Zn} + {HNO}_3 \, ({dilute}) \rightarrow {Zn(NO}_3)_2 + {H}_2{O} + Y \]

Which of the following is useful to verify the charge on colloidal particles?

Identify the correct statements from the following:
[I.] At constant pressure, physical adsorption decreases with increase in temperature.
[II.] Enthalpy of physisorption is higher than enthalpy of chemisorption.
[III.] Gas mask used in coal mines consists of activated charcoal.

The rate constant of a first order reaction at 400 K and 500 K is respectively $ 2 \times 10^{-5} \, {s}^{-1} $ and $ 4 \times 10^{-3} \, {s}^{-1} $. What is the approximate activation energy (in kJ/mol$^{-1}$)? (R = 8.3 J mol$^{-1}$ K$^{-1}$, log 2 = 0.3)

At 298 K, the density of an aqueous solution containing 82 g of acetic acid per dm$^3$ is 1.01 kg dm$^{-3}$. If the molarity of the solution is $x$ M, the molality $m$ of the same solution is (molar mass of acetic acid = 60 g mol$^{-1}$):

X-ray diffraction studies show that a metal 'M' crystallises in an fcc unit cell with edge length of 400 pm. If the density of the metal is $7.5 \times 10^3 { kg/m}^{-3}$, the number of unit cells present in 0.015 kg of it is:

What is the percentage of carbon in the compound X, formed in the given sequence of reactions?

A $_{92}^{238}U$ nucleus decays to a $_{82}^{206}Pb$ nucleus. The number of $ \alpha $ and $ \beta^- $ particles emitted are?

In Kjeldahl's method of estimation of nitrogen, the ammonia evolved from 0.2 g of an organic compound was absorbed in 60 mL of 0.1 M $H_2SO_4$. If 40 mL of 0.1 M NaOH is required for complete neutralisation of the unused acid, the percentage of nitrogen in the compound is:

If the mean of the data 7, 8, 9, 7, 8, 7, $\lambda$, 8 is 8, then the variance of the data:

Which one of the following pairs of gases does not represent the greenhouse gases?