JEE Main 2024 (Online) 30th January Morning Shift

Primary coil of a transformer is connected to \(220 \mathrm{~V}\) ac. Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistances shown in figure. The outpu...

A series L.R circuit connected with an ac source \(E=(25 \sin 1000 t) V\) has a power factor of \(\frac{1}{\sqrt{2}}\). If the source of emf is changed to \(\mathrm{E}=(20 \sin 2000 \mathrm{t}) \mathrm{V}\), the new power factor of the circ...

The ratio of the magnitude of the kinetic energy to the potential energy of an electron in the 5th excited state of a hydrogen atom is :

A electron of hydrogen atom on an excited state is having energy \(\mathrm{E}_{\mathrm{n}}=-0.85 \mathrm{~eV}\). The maximum number of allowed transitions to lower energy level is _________.

A capacitor of capacitance \(\mathrm{C}\) and potential \(\mathrm{V}\) has energy \(\mathrm{E}\). It is connected to another capacitor of capacitance \(2 \mathrm{C}\) and potential \(2 \mathrm{~V}\). Then the loss of energy is $$\frac{x}{3}...

A spherical body of mass \(100 \mathrm{~g}\) is dropped from a height of \(10 \mathrm{~m}\) from the ground. After hitting the ground, the body rebounds to a height of \(5 \mathrm{~m}\). The impulse of force imparted by the ground to the bo...

A potential divider circuit is shown in figure. The output voltage V\(_0\) is :

An electric toaster has resistance of \(60 \Omega\) at room temperature \(\left(27^{\circ} \mathrm{C}\right)\). The toaster is connected to a \(220 \mathrm{~V}\) supply. If the current flowing through it reaches \(2.75 \mathrm{~A}\), the te...

Two cells are connected in opposition as shown. Cell \(\mathrm{E}_1\) is of \(8 \mathrm{~V}\) emf and \(2 \Omega\) internal resistance; the cell \(\mathrm{E}_2\) is of \(2 \mathrm{~V}\) emf and \(4 \Omega\) internal resistance. The terminal...

The work function of a substance is \(3.0 \mathrm{~eV}\). The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately;

A ceiling fan having 3 blades of length \(80 \mathrm{~cm}\) each is rotating with an angular velocity of 1200 \(\mathrm{rpm}\). The magnetic field of earth in that region is \(0.5 \mathrm{G}\) and angle of dip is \(30^{\circ}\). The emf ind...

The electric field of an electromagnetic wave in free space is represented as \(\overrightarrow{\mathrm{E}}=\mathrm{E}_0 \cos (\omega \mathrm{t}-\mathrm{kz}) \hat{i}\). The corresponding magnetic induction vector will be :

A Zener diode of breakdown voltage \(10 \mathrm{~V}\) is used as a voltage regulator as shown in the figure. The current through the Zener diode is :

The electrostatic potential due to an electric dipole at a distance '\(r\)' varies as :

The distance between object and its two times magnified real image as produced by a convex lens is \(45 \mathrm{~cm}\). The focal length of the lens used is _______ cm.

The gravitational potential at a point above the surface of earth is \(-5.12 \times 10^7 \mathrm{~J} / \mathrm{kg}\) and the acceleration due to gravity at that point is \(6.4 \mathrm{~m} / \mathrm{s}^2\). Assume that the mean radius of ear...

Two thermodynamical processes are shown in the figure. The molar heat capacity for process A and B are \(\mathrm{C}_{\mathrm{A}}\) and \(\mathrm{C}_{\mathrm{B}}\). The molar heat capacity at constant pressure and constant volume are represe...

At which temperature the r.m.s. velocity of a hydrogen molecule equal to that of an oxygen molecule at \(47^{\circ} \mathrm{C}\) ?

All surfaces shown in figure are assumed to be frictionless and the pulleys and the string are light. The acceleration of the block of mass \(2 \mathrm{~kg}\) is :

The horizontal component of earth's magnetic field at a place is \(3.5 \times 10^{-5} \mathrm{~T}\). A very long straight conductor carrying current of \(\sqrt{2} \mathrm{~A}\) in the direction from South east to North West is placed. The f...

Two insulated circular loop A and B of radius '\(a\)' carrying a current of '\(\mathrm{I}\)' in the anti clockwise direction as shown in the figure. The magnitude of the magnetic induction at the centre will be :

The displacement and the increase in the velocity of a moving particle in the time interval of \(t\) to \((t+1) \mathrm{s}\) are \(125 \mathrm{~m}\) and \(50 \mathrm{~m} / \mathrm{s}\), respectively. The distance travelled by the particle i...

Young's modules of material of a wire of length '\(L\)' and cross-sectional area \(A\) is \(Y\). If the length of the wire is doubled and cross-sectional area is halved then Young's modules will be :

Each of three blocks \(\mathrm{P}, \mathrm{Q}\) and \(\mathrm{R}\) shown in figure has a mass of \(3 \mathrm{~kg}\). Each of the wires \(\mathrm{A}\) and \(\mathrm{B}\) has cross-sectional area \(0.005 \mathrm{~cm}^2\) and Young's modulus $...

A particle of mass \(\mathrm{m}\) is projected with a velocity '\(\mathrm{u}\)' making an angle of \(30^{\circ}\) with the horizontal. The magnitude of angular momentum of the projectile about the point of projection when the particle is at...

Consider a Disc of mass \(5 \mathrm{~kg}\), radius \(2 \mathrm{~m}\), rotating with angular velocity of \(10 \mathrm{~rad} / \mathrm{s}\) about an axis perpendicular to the plane of rotation. An identical disc is kept gently over the rotat...

Match List I with List II.

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The diffraction pattern of a light of wavelength \(400 \mathrm{~nm}\) diffracting from a slit of width \(0.2 \mathrm{~mm}\) is focused on the focal plane of a convex lens of focal length \(100 \mathrm{~cm}\). The width of the $$1^{\text {st...

In a closed organ pipe, the frequency of fundamental note is \(30 \mathrm{~Hz}\). A certain amount of water is now poured in the organ pipe so that the fundamental frequency is increased to \(110 \mathrm{~Hz}\). If the organ pipe has a cros...

A particle is placed at the point \(A\) of a frictionless track \(A B C\) as shown in figure. It is gently pushed towards right. The speed of the particle when it reaches the point B is : (Take \(g=10 \mathrm{~m} / \mathrm{s}^2\)).