List of top Questions asked in MHT CET- 2021

For a reaction $\mathrm{A} \rightarrow \text{product}$, rate constant is $2 \times 10^{-2}\ \mathrm{s}^{-1}$. The initial concentration of A is $1.0\ \mathrm{mol\ dm}^{-3}$. What is the value of $\log_{10}\!\left(\frac{1}{[\mathrm{A}]_t}\right)$ after 100 seconds?
What is the number of octahedral and tetrahedral voids presents respectively in 0.25 mole of a substance having hcp structure?
When tert-butyl bromide is heated with silver fluoride, the major product obtained is
A step-down transformer has a turns ratio of $20 : 1$. If $8\text{ V}$ is applied across a $0.4\ \Omega$ secondary load, then the primary current will be
Choose the correct statement. In semiconductors, the valence band and conduction band are
The relative permeability of iron is 2000. Its absolute permeability in SI unit will be [$\frac{\mu_0}{4\pi} = 10^{-7}\text{ T}\cdot\text{m}\cdot\text{A}^{-1}$]
An ideal gas at $27^\circ\text{C}$ is compressed adiabatically to $\left(\frac{8}{27}\right)$ of its original volume. If the ratio of specific heats, $\gamma = \frac{5}{3}$ then the rise in temperature of the gas is
Two radioactive materials $X_1$ and $X_2$ have decay constants '$5\lambda$' and '$\lambda$' respectively. Initially, they have the same number of nuclei. After time '$t$', the ratio of number of nuclei of $X_1$ to that of $X_2$ is $\frac{1}{e}$. Then $t$ is equal to
If two sources emit light waves of different amplitudes then
Photons of energy $10\text{ eV}$ are incident on a photosensitive surface of threshold frequency $2 \times 10^{15}\text{ Hz}$. The kinetic energy in eV of the photoelectrons emitted is [Planck's constant $h = 6.63 \times 10^{-34}\text{ Js}$]
The magnetic field inside a current carrying toroidal solenoid is $0.2\text{ mT}$. What is the magnetic field inside the toroid if the current through it is tripled and the cross-sectional radius is made $\frac{1}{3}^{\text{rd}}$?
Two particles $A$ and $B$ having same mass have charge $+q$ and $+4q$ respectively. When they are allowed to fall from rest through same electric potential difference, the ratio of their speeds $V_A$ to $V_B$ will become
If '$E$' and '$L$' denote the magnitude of total energy and angular momentum of a revolving electron in the $n^{\text{th}}$ Bohr orbit, then
The magnetic flux (in weber) in a closed circuit of resistance $20\ \Omega$ varies with time $t$ second according to equation $\phi = 5t^2 - 6t + 9$. The magnitude of induced current at $t = 0.2$ second is
A body of mass '$m$' performs linear S.H.M. given by the equation $x = P \sin \omega t + Q \sin \left(\omega t + \frac{\pi}{2}\right)$. The total energy of the particle at any instant is
'n' waves are produced on a string in 1 second. When the radius of the string is doubled, keeping tension same, the number of waves produced in 1 second for the same harmonic will be
The light of wavelength '$\lambda$' is incident on the surface of metal of work function $\phi$ and emits the electron. The maximum velocity of electron emitted is [$m = \text{mass of electron and } h = \text{Planck's constant, } c = \text{velocity of light}$]
A parallel plate capacitor having plates of radius $6\text{ cm}$ has capacitance $100\text{ pF}$. It is connected to $230\text{ V}$ a.c. supply with angular frequency $300\text{ rad/s}$. The r.m.s. value of current is
For the circuit shown below, instantaneous current through inductor '$L$' and capacitor '$C$' is respectively
At a height 'R' above the earth's surface the gravitational acceleration is (R = radius of earth, g = acceleration due to gravity on earth's surface)
A step-down transformer is used to reduce the main supply from $V_1$ volt to $V_2$ volt. The primary coil draws a current $I_1$ A and the secondary coil draws $I_2$ A ($I_1 \lt I_2$). The ratio of input power to output power is
Two rings of radius 'R' and 'nR' made of same material have the ratio of moment of inertia about an axis passing through its centre and perpendicular to the plane is $1 : 8$. The value of 'n' is (mass per unit length = $\lambda$)
A child is standing with folded hands at the centre of the platform rotating about its central axis. The kinetic energy of the system is '$K$'. The child now stretches his arms so that the moment of inertia of the system becomes double. The kinetic energy of the system now is
A needle is $7\text{ cm}$ long. Assuming that the needle is not wetted by water, what is the weight of the needle, so that it should float on water surface? [Surface tension of water = $70\text{ dyn/cm}$, $g = 980\text{ cm/s}^2$]
An ideal gas having molar mass $M_0$, has r.m.s. velocity $V$ at temperature $T$. Then