JEE Main Practice Test- 19 - JEE MCQ

If A is the mass no. of an element, then volume of the nucleus of an atom of this element is proportional to

When X-rays pass through a strong uniform magnetic field, then they

The r.m.s. value of an a.c. of 50 Hz is 10A. The time taken by a.c. in reaching from zero to maximum value and the peak value of current will be

An electric dipole is placed along the X-axis at the origin O. A point P is at a distance of 20 cm from this origin such that OP makes an angle π/3 with the X axis. If electric field at P makes an angle θ with X-axis, the value of θ is

A ball of wt. 0.1 kg coming with speed 30 m/s strikes with a bat and returns in opposite direction with speed 40 m/s, then impulse is

Electric field at the centroid of a triangle carrying q charge at each corner is

A monkey of mass 20 kg is holding a vertical rope. The rope will not break when a mass of 25 kg is suspended from it, but will break if the mass exceeds 25 kg. What is the maximum acceleration, with which the monkey can climb up along the rope? (Take g = 10 m−s⁻²)

A galvanometer having a resistance of 8 Ω is shunted by a wire of resistance 2 Ω. If the total current is 1 A, then current passing through the shunt will be

The logic circuit shown below has the input wave forms 'A' and 'B' as shown. Pick out the correct output wave form.

A motor boat of mass 300 kg is standing in water. If the area of the bottom surface is 120 m², then the boat will exert a pressure of (Take g=10 m-s⁻²)

The function of the moderator in a nuclear reactor is

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Speed of light in water is less than the speed in air.
Reason(R): Refractive index of water is greater than one .

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): In general magnetic force between two charges is much smaller compared to the electric force .
Reason(R): In general velocity of charges << velocity of light in free space.

For motion in a plane with constant acceleration, a → , initial velocity v 0 → and final velocity ν → after time t, we have

The least coefficient of friction for an inclined plane inclined at angle α with horizontal in order that a solid cylinder will roll down it without slipping is

A measure of the degree of disorder of a system is known as

In young's double slit experiment, the intensity of central maximum is I. It one slit is closed, the intensity at the same place will become

The energy density and pressure have

A wavefront is an imaginary surface where

A transverse progressive wave is given by the equation y = 2 cos [π (0.5x - 200t)], where x and y are in cm and t in sec. Which of the following statement is true for this wave

Which one of the following statements is WRONG in the context of X-rays generated from a X-ray tube ?

A condenser is connected across another charged condenser. The energy in the two condenser will be

A tachometer is a device to measure

In an experiment to measure the internal resistance of a cell, by a potentiometer, it is found that the balance point is at a length of 2 m, when the cell is shunted by a 5 Ω resistance and is at a length of 3m when the cell is shunted by a 10 Ω resistance. The internal resistance of the cell is

The figure to the right shows an edge-on view of three extremely large, parallel insulating sheets positively charged with uniform and identical surface charge densities. In which of the regions shown is the electric field a maximum?

Cathode rays enter into a uniform magnetic field perpendicular to the direction of the field. In the magnetic field their path will be