Sign in
Please select an account to continue using cracku.in
↓ →
JEE WhatsApp Group
Join Our JEE Preparation Group
Prep with like-minded aspirants; Get access to free daily tests and study material.
The period of oscillation of a simple pendulum is $$T = 2\pi\sqrt{\frac{L}{g}}$$. Measured value of $$L$$ is 1.0 m from meter scale having a minimum division of 1 mm and time of one complete oscillation is 1.95 s measured from stopwatch of 0.01 s resolution. The percentage error in the determination of $$g$$ will be:
Login to view the detailed solution.
A particle is projected with velocity $$v_0$$ along $$x$$-axis. A damping force is acting on the particle which is proportional to the square of the distance from the origin i.e. $$ma = -\alpha x^2$$. The distance at which the particle stops:
Login to view the detailed solution.
A circular hole of radius $$\frac{a}{2}$$ is cut out of a circular disc of radius $$a$$ as shown in figure. The centroid of the remaining circular portion with respect to point O will be:
Login to view the detailed solution.
.webp)
A body weighs 49 N on a spring balance at the north pole. What will be its weight recorded on the same weighing machine, if it is shifted to the equator?
[Use $$g = \frac{GM}{R^2} = 9.8$$ m s$$^{-2}$$ and radius of earth, $$R = 6400$$ km.]
Login to view the detailed solution.
If one mole of an ideal gas at $$(P_1, V_1)$$ is allowed to expand reversibly and isothermally (A to B) its pressure is reduced to one-half of the original pressure (see figure). This is followed by a constant volume cooling till its pressure is reduced to one-fourth of the initial value $$(B \to C)$$. Then it is restored to its initial state by a reversible adiabatic compression (C to A). The net work done by the gas is equal to:
Login to view the detailed solution.
On the basis of kinetic theory of gases, the gas exerts pressure because its molecules:
Login to view the detailed solution.
.webp)
In the given figure, a body of mass $$M$$ is held between two massless springs, on a smooth inclined plane. The free ends of the springs are attached to firm supports. If each spring has spring constant $$k$$, the frequency of oscillation of given body is:
Login to view the detailed solution.
When a particle executes SHM, the nature of graphical representation of velocity as a function of displacement is:
Login to view the detailed solution.
Which of the following equations represents a travelling wave?
Login to view the detailed solution.
.webp)
Two electrons each are fixed at a distance 2d. A third charge proton placed at the midpoint is displaced slightly by a distance $$x (x \ll d)$$ perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency:
($$m$$ = mass of charged particle)
Login to view the detailed solution.
A soft ferromagnetic material is placed in an external magnetic field. The magnetic domains:
Login to view the detailed solution.
The figure shows a circuit that contains four identical resistors with resistance $$R = 2.0$$ $$\Omega$$, two identical inductors with inductance $$L = 2.0$$ mH and an ideal battery with E.M.F. $$E = 9$$ V. The current $$i$$ just after the switch $$S$$ is closed will be:
Login to view the detailed solution.
.webp)
An X-ray tube is operated at 1.24 million volt. The shortest wavelength of the produced photon will be:
Login to view the detailed solution.
Match List - I with List - II.
| List-I | List-II |
|---|---|
| (a) Source of microwave frequency | (i) Radioactive decay of nucleus |
| (b) Source of infrared frequency | (ii) Magnetron |
| (c) Source of Gamma Rays | (iii) Inner shell electrons |
| (d) Source of X-rays | (iv) Vibration of atoms and molecules |
| (v) LASER | |
| (vi) RC circuit |
Login to view the detailed solution.
If the source of light used in a Young's double slit experiment is changed from red to violet:
Login to view the detailed solution.
The de Broglie wavelength of a proton and $$\alpha$$-particle are equal. The ratio of their velocities is
Login to view the detailed solution.
According to Bohr atom model, in which of the following transitions will the frequency be maximum?
Login to view the detailed solution.
The logic circuit shown above is equivalent to:
Login to view the detailed solution.
Zener breakdown occurs in a $$p - n$$ junction having $$p$$ and $$n$$ both:
Login to view the detailed solution.
Given below are two statements:
Statement I: $$p - n$$ junction diodes can be used to function as a transistor, simply by connecting two diodes, back to back, which acts as the base terminal.
Statement II: In the study of transistors, the amplification factor $$\beta$$ indicates ratio of the collector current to the base current.
In the light of the above statements, choose the correct answer from the options given below.
Login to view the detailed solution.
Two solids $$A$$ and $$B$$ of mass 1 kg and 2 kg respectively are moving with equal linear momentum. The ratio of their kinetic energies $$(K.E.)_A : (K.E.)_B$$ will be $$\frac{A}{1}$$, so the value of $$A$$ will be ______.
Login to view the detailed solution.
A uniform thin bar of mass 6 kg and length 2.4 meter is bent to make an equilateral hexagon. The moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is ______ $$\times 10^{-1}$$ kg m$$^2$$.
Login to view the detailed solution.
A uniform metallic wire is elongated by 0.04 m when subjected to a linear force $$F$$. The elongation, if its length and diameter is doubled and subjected to the same force will be ______ cm.
Login to view the detailed solution.
The root-mean-square speed of molecules of a given mass of a gas at 27°C and 1 atmosphere pressure is 200 m s$$^{-1}$$. The root-mean-square speed of molecules of the gas at 127°C and 2 atmosphere pressure is $$\frac{x}{\sqrt{3}}$$ m s$$^{-1}$$. The value of $$x$$ will be ______.
Login to view the detailed solution.
Two cars are approaching each other at an equal speed of 7.2 km hr$$^{-1}$$. When they see each other, both blow horns having a frequency of 676 Hz. The beat frequency heard by each driver will be ______ Hz. [Velocity of sound in air is 340 m s$$^{-1}$$.]
Login to view the detailed solution.
A point charge of $$+12$$ $$\mu C$$ is at a distance 6 cm vertically above the centre of a square of side 12 cm as shown in figure. The magnitude of the electric flux through the square will be ______ $$\times 10^3$$ N m$$^2$$ C$$^{-1}$$.
Login to view the detailed solution.
A cylindrical wire of radius 0.5 mm and conductivity $$5 \times 10^7$$ S m$$^{-1}$$ is subjected to an electric field of 10 mV m$$^{-1}$$. The expected value of current in the wire will be $$x^3\pi$$ mA. The value of $$x$$ is ______.
Login to view the detailed solution.
A series LCR circuit is designed to resonate at an angular frequency $$\omega_0 = 10^5$$ rad s$$^{-1}$$. The circuit draws 16 W power from 120 V source at resonance. The value of resistance $$R$$ in the circuit is ______ $$\Omega$$.
Login to view the detailed solution.
An electromagnetic wave of frequency 3 GHz enters a dielectric medium of relative electric permittivity 2.25 from vacuum. The wavelength of this wave in that medium will be ______ $$\times 10^{-2}$$ cm.
Login to view the detailed solution.
A signal of 0.1 kW is transmitted in a cable. The attenuation of cable is $$-5$$ dB per km and cable length is 20 km. The power received at the receiver is $$10^{-x}$$ W. The value of $$x$$ is ______. [Gain in dB = $$10 \log_{10}\left(\frac{P_O}{P_i}\right)$$]
Login to view the detailed solution.
Educational materials for JEE preparation
Share