JEE Main Mock Test - 17 - JEE MCQ

Young's double slit expetiment is performed using light of wavelength λ. One of the slits is covered by a thin glass sheet of refractive index μ at this wavelength. The smallest thickness of the sheet to bring the adjacent minimum to the centre of the screen is

The current I drawn from a 5 volt source will be

In the circuit shown in figure, A and B are two cells of the same emf, E and of internal resistances r_A and r_B, respectively. L is an ideal inductor and C is an ideal capacitor. The key K is closed. When the current in the circuit becomes steady, what should be the value of R so that the potential difference across the terminals of cell A is zero?

A coil of inductance 0.20 H is connected in series with a switch and a cell of emf 1.6 V. The total resistance of the current is 4.0Ω. What is the initial rate of growth of the current when the switch is closed?

Mass of the earth is 81 times the mass of the moon and the distance between the earth and moon is 60 times the radius of the earth. If R is the radius of the earth, then the distance between the moon and the point on the line joining the moon and earth where the gravitational force becomes zero is

A magnet of magnetic moment M and length 2l is bent at its mid-point such that the angle of bending is 60°. Now, the magnetic moment is

Three identical uniform rods of the same mass M and length L are arranged in xy plane as shown in the figure. A fourth uniform rod of mass 3 M has been placed as shown in the xy plane. What should be the value of the length of the fourth rod such that the centre of mass of all the four rods lie at the origin?

A metallic wire with tension T and at temperature 30°C vibrates with its fundamental frequency of 1 kHz. The same wire with the same tension but at 10°C temperature vibrates with a fundamental frequency of 1.001 kHz. The coefficient of linear expansion of the wire is

For a gas, the difference between the two specific heats at constant pressure and constant volume is 4150 J kg^-1 K^-1 and their ratio is 1.4. What is the specific heat of the gas at constant volume in units of J kg^-1 k^-1?

Among the following pairs, which one does not have identical dimensions?

Which of the following pairs of physical quantities does not have same dimensional formula ?

A plank is held at an angle αα to the horizontal on two fixed supports A and B. The plank can slide against the supports (without friction) because of its weight MgMg. Acceleration and direction in which a man of mass mm should move so that the plank does not move is:

A force is acting at a point . The value of αα for which angular momentum about origin is conserved is:

A simple pendulum of length ll is suspended from the ceiling of a cart which is sliding without friction on an inclined plane of inclination θ. What will be the time period of the pendulum?

The frequency of a sonometer wire is f but when the weights producing tension are completely immersed in water the frequency becomes f/2 and on immersing the weights in certain liquid the frequency becomes f/3. The specific gravity of the liquid is

Which of these is correct in regard to a magnet?

The mean lives of radioactive substances are 1620 y and 405 y for α- emission and β- emission respectively. Find out the time during which three-fourth of a sample will decay if it is decaying both by α- emission and β- emission simultaneously.

Two astronauts have deserted their spaceship in a region of space far from the gravitational attraction of any other body. Each has a mass of 100 kg and they are 100 m apart. They are initially at rest relative to each other. How long (in number of days) will it be before the gravitational attraction brings them 1 cm closer together? (Nearest integer)

An object O is placed at a distance of 20 cm from a thin plano-convex lens of focal length 15 cm. The plane surface of the lens is silvered as shown in the figure below:

The image is formed at a distance of ___ cm to the left of the lens. Fill in the blank with appropriate integer.

Water is drawn from a well into a 5 kg drum of capacity 55 litres, by two ropes connected to the top of the drum. The linear mass density of each rope is 0.5 kg m^-1. The work done in lifting water to the ground from the surface of water in the well 20 m below is c × 104 J. The value of c, up to one decimal place, is [g = 10 ms^-2]

(Nearest integer)

An iron bar of length 10 m is heated from 0 °C to 100 °C. If the coefficient of linear thermal expansion of iron is 10×10⁻⁶ °C⁻¹, the increase in the length of the bar in cm is

An uncharged capacitor of capacitance 4 μF and a resistance of 2.5 MΩ are connected in series with 12 V battery at t = 0. Find the time in seconds (approximate to the nearest integer) after which the potential difference across the capacitor is three times the potential difference across the resistor. [Given, ln(2) = 0.693]

The reaction, N₂(g) + 3H₂(g) ⇌ 2NH₃(g) is exothermic and reversible. A mixture of N₂(g),H₂(g) and NH₃(g) is at equilibrium in a closed container. When a certain quantity of extra H₂(g) is introduced into the container, while keeping the volume constant, then which statement among the following is true?

What is the pH of 0.01M glycine solution? For glycine K_a1 = 4.5 × 10⁻³ and K_a2 = 1.7 × 10⁻¹⁰ at 298 K

The precipitate of Al(OH)₃ dissolves in NaOH solution. It is due to the formation of

Sulphuric acid reacts with PCl₅ to give

For all x, y ∈ R, the maximum value of sin²x + sin²y + sin²(x + y) equals