JEE Main Mock Test - 16 - JEE MCQ

A particle of charge q and mass m moves in a circular orbit of radius r with the angular speed ω. The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on

If a wire is stretched to make it 0.1% longer, its resistance will

Directions: The following question contains statement-1 and statement-2. Of the four choices given, choose the one that best describes the two statements.

Statement-1: For a mass M kept at the centre of a cube of side a, the flux of gravitational field passing through its sides is 4πGM.

Statement-2: If the direction of a field due to a point source is radial and its dependence on the distance r from the source is given as 1/r², its flux through a closed surface depends only on the strength of the source enclosed by the surface and not on the size or shape of the surface.

When the current in the portion of the circuit, shown in the figure, is 2 A and is increasing at the rate of 1 A/s, then the measured potential difference V_ab is 8 V. However, when the current is 2 A and is decreasing at the rate of 1 A/s, the measured potential difference V_ab is 4V. The values of R and L are

A particle of mass m is at rest at the origin at time t = 0. It is subjected to a force F(t) = F₀e^-bt in the x direction.

Which of the following curves depicts its speed v(t)?

A wire elongates by l mm when a load W is hanged from it. If the wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be (in mm)

Two particles, A and B, of equal masses are suspended from two massless springs of spring constants k₁ and k₂, respectively. If the maximum velocities, during oscillations, are equal, then the ratio of amplitudes of A and B is

The amplitude of wave disturbance propagating in the positive x-axis is given by at t = 0 and at t = 2s, where x and y are in metres. The shape of the disturbance does not change during the propagation. The velocity of the wave is

Two cylindrical rods of uniform cross-sectional area A and 2A, having free electrons per unit volume 2n and n respectively are joined in series. A constant current I flows through them in steady state. The ratio of the drift velocity of free electrons in the left rod to that of the right rod is

Water is filled up to a height h in a cylindrical vessel. It takes time t to completely drain the vessel by means of a small hole at the bottom. If water is filled up to a height 4h then the time it takes to completely drain the vessel is

A refrigerator is to maintain the eatables, kept inside it, at 9°C. The coefficient of performance of the refrigerator, if the room temperature is 36°C, is

An elevator is going upward with an acceleration a = g/4 and a ball is released from rest relative to the elevator at a distance h₁ above the floor. The speed of the elevator at the time of ball release is v₀. Then the bounce height h₂ of the ball with respect to the elevator is (the coefficient of restitution for the impact is e)

The magnetic flux through a circuit of resistance R changes by an amount Δϕ in a time Δt. The total magnitude of electric charge Q, that passes through any point in the circuit during this time is

To get maximum current through a resistance of 2.5 Ω, one can use mm rows of cells, each row having n cells. The internal resistance of each cell is 0.5 Ω. What are the values of n & m, if the total number of cells is 45?.

An iron wire AB of length 3 m at 0°C is stretched between the opposite walls of a brass casing at 0°C0°C as shown in the figure below. The diameter of the wire is m0.6 mm. What extra tension will be set up in the wire when the temperature of the system is raised to 40°C?

Given α_brass = 18 × 10⁻⁶ K⁻¹, α_iron= 12 × 10⁻⁶ K⁻¹, Y_iron = 21 × 10¹⁰ N m⁻²

The angular width of the central maximum in the Fraunhofer's diffraction pattern is measured. The slit is illuminated by the light of wavelength 6000 Å. If the slit is illuminated by the light of another wavelength, angular width decreases by 30% . The wavelength of light used is

What will be the displacement equation of the simple harmonic motion obtained by combining the motions?

(Note: ϕ is an acute angle)

The minimum frequency of a γ-ray that causes a deuteron to disintegrate into a proton and a neutron is p × 10²⁰ Hz. The value of p is (Nearest integer)

(Given, m_d = 2.0141 a.m.u., m_p = 1.0078 a.m.u. and m_n = 1.0087 a.m.u.)

The magnetic field in a travelling electromagnetic wave has a peak value of 20 nT. The peak value of electric field strength (in V/m) is

Three rods of copper, brass and steel are welded together to form a Y-shaped structure. Area of cross-section of each rod = 4 cm². End of copper rod is maintained at 100°C, whereas ends of brass and steel are kept at 0°C. Lengths of the copper, brass and steel rods are 46, 13 and 12 cm. respectively. The rods are thermally insulated from surroundings except at ends. Thermal conductivities of copper, brass and steel are 0.92, 0.26 and 0.12 CGS units. respectively. Rate of heat flow (in cal/s) through copper rod is

(Nearest integer)

The forward-bias voltage of a diode is changed from 0.6 V to 0.7 V, the current changes from 5 mA to 15 mA. What is the value of the forward bias resistance?

The precipitate of Ag₂CrO₄(K_sp = 1.9 × 10⁻¹²) is obtained when equal volumes of the following are mixed.

Identify the least stable ion.

The reaction, 2SO_2(g) + O_2(g) → 2SO₃(g) is carried out in a 1 dm³ vessel and a 2 dm³ vessel, separately. The ratio of the reaction velocities, respectively, will be

Cyanide process is used for the extraction of

KO₂ (potassium superoxide) is used in oxygen cylinders in space and submarines because it

Which of the following dissolves in water but does not give any oxyacid solution?