Practice Questions

Q20.Identify the operation performed by the circuit given below : (1) NAND (2) OR (3) AND (4) NOT

Q20.Two Zener diodes ( A and B) having breakdown voltages of 6 V and 4 V respectively, are connected as shown in the circuit below. The output voltage V0 variation with input voltage linearly increasing with time, is given by ( Vinput = 0V at t = 0) (1) (2) (3) (4) JEE Main 2020 (05 Sep Shift 2) JEE Main Previous Year Paper

Q20.The least count of the main scale of a vernier calipers is 1 mm. Its vernier scale is divided into 10 divisions and coincide with 9 divisions of the main scale. When jaws are touching each other, the 7th division of the vernier scale coincides with a division of the main scale and the zero of vernier scale is lying right side of the zero of the main scale. When this vernier is used to measure the length of the cylinder the zero of the vernier scale between 3. 1 cm and 3. 2 cm and 4th VSD coincides with the main scale division. The length of the cylinder is (VSD is vernier scale division) (1) 3. 2 cm (2) 3. 21 cm (3) 3. 07 cm (4) 2. 99 cm

Q20.With increasing biasing voltage of a photo diode, the photocurrent magnitude: (1) remains constant (2) increases initially and after attaining certain value, it decreases (3) increases linearly (4) increases initially and saturates finally

Q20.A screw gauge has 50 divisions on its circular scale. The circular scale is 4 units ahead of the pitch scale marking, prior to use. Upon one complete rotation of the circular scale, a displacement of 0. 5 mm is noticed on the pitch scale. The nature of zero error involved and the lest count of the screw gauge, are respectively: (1) Negative, 2μm (2) Positive 10μm (3) Positive 0. 1mm (4) Positive, 0. 1μm

Q20.In the following, digital circuit, what will be the output a ' Z', when the input (A, B) are (1, 0), (0, 0), (1, 1), (0, 1) (1) 0, 0, 1, 0 (2) 1, 0, 1, 1 (3) 1, 1, 0, 1 (4) 0, 1, 0, 0

Q20.If a semiconductor photo diode can detect a photon with a maximum wavelength of 400 nm, then its band gap energy is: Planck's constant h = 6. 63 × 10−34 J. s Speed of light c = 3 × 108 m s−1 (1) 1. 1 eV (2) 2. 0 eV (3) 1. 5 eV (4) 3. 1 eV

Q20.Boolean relation at the output stage- Y for the following circuit is: (1) − − (2) A + B A + B (3) A ∙B (4) − − A ∙ B

Q20.Take the breakdown voltage of the zener diode used in the given circuit as 6V . For the input voltage shown in the figure below, the time variation of the output voltage is: (Graphs drawn are schematic and not to the scale) JEE Main 2020 (04 Sep Shift 1) JEE Main Previous Year Paper (1) (2) (3) (4)

Q20.A student measuring the diameter of a pencil of circular cross-section with the help of a vernier scale records the following four readings 5. 50 mm, 5. 55 mm, 5. 34 mm , 5. 65 mm . The average of these four reading is 5. 5375 mm and the standard deviation of the data is 0. 07395 mm. The average diameter of the pencil should therefore be recorded as : (1) (5 .5375 ±0 .0739) mm (2) (5 .5375 ±0 .0740) mm (3) (5 .538 ±0 .074) mm (4) (5 .54 ±0 .07) mm

Q20.In the given circuit, value of Y is: (1) 0 (2) toggles between 0 and 1 (3) will not execute (4) 1 JEE Main 2020 (08 Jan Shift 2) JEE Main Previous Year Paper

Q20.Which of the following gives a reversible operation? (1) (2) (3) (4)

Q20.Using screw gauge of pitch 0. 1 cm and 50 divisions on its circular scale, the thickness of an object is measured. It should correctly be recorded as, (1) 2. 121 cm (2) 2. 124 cm (3) 2. 125 cm (4) 2. 123 cm

Q21.The sum of two forces P and Q is R such that R = P . Find the angle between resultant of 2P and Q and Q , ________ JEE Main 2020 (07 Jan Shift 2) JEE Main Previous Year Paper

Q21.A square shaped hole of side l = 2a is carved out at a distance d = a2 from the centre ' O ' of a uniform circular disk of radius a. If the distance of the centre of mass of the remaining portion from O is −ax , value of X (to the nearest integer) is :

Q21.Starting at temperature 300K, one mole of an ideal diatomic gas (γ = 1.4) is first compressed adiabatically from volume V1 to V2 = V116 . It is then allowed to expand isobarically to volume 2V2 . If all the processes are the quasi-static then the final temperature of the gas (in oK ) is (to the nearest integer) ___________. →

Q21.The distance x covered by a paritcle in one dimensional motion varies with time t as x2 = at2 + 2bt + c . If the acceleration of the particle depends on x as x−n , where n is an integer, the value of n is _________

Q21.A body of mass 2 kg is driven by an engine delivering a constant power of 1 J s−1. the body starts from rest and moves in a straight line. After 9 s, the body has moved a distance (in m)….

Q21.The speed verses time graph for a particle is shown in the figure. The distance travelled (in m) by the particle during the time interval t = 0 to t = 5 s will be __________

Q21.A particle (m = 1kg) slides down a frictionless track (AOC) starting from rest at a point A (height 2m ). After reaching C, the particle continues to move freely in air as a projectile. When it reaching its highest point P (height 1m ), the kinetic energy of the particle (in J ) is: (Figure drawn is schematic and not to scale; take g = 10ms−2 ) ______________.

Q21.The density of a solid metal sphere is diameter. The maximum error in the density of the sphere is ( 100x )%. If the relative errors in measuring the mass and the diameter are 6. 0% and 1. 5% respectively, the value of x is −

Q21.A block starts moving up an inclined plane of inclination 30° with an initial velocity of v0 . It comes back to its initial position with velocity v0 2 . The value of the coefficient of kinetic friction between the block and the inclined plane is close to 1 , The nearest integer to I is : 1000

Q21.A particle of mass 200 MeV c−2 collides with a hydrogen atom at rest. Soon after the collision, the particle comes to rest, and the atom recoils and goes to its first excited state. The initial kinetic energy of the particle (in eV ) is N4 . The value of N is: (Given the mass of the hydrogen atom to be 1 GeV c−2 )......... → + 2ˆj + m . Then the magnitude of torque about the point N acts at a point (4ˆi + 3ˆj −ˆk)

Q21.A small block starts slipping down from a point B on an inclined plane AB, which is making an angle θ with the horizontal section BC is smooth and the remaining section CA is rough with a coefficient of friction μ. It is found that the block comes to rest as it reaches the bottom (point A) of the inclined plane. If BC = 2AC , the coefficient of friction is given by μ = k tanθ . The value of k is ....... JEE Main 2020 (02 Sep Shift 1) JEE Main Previous Year Paper

Q21. ABC is a plane lamina of the shape of an equilateral triangle. D, E are mid-points of AB, AC and G is the centroid of the lamina. Moment of inertia of the lamina about an axis passing through G and perpendicular to the plane ABC is I0 . If part ADE is removed, the moment of inertia of the remaining part about the same axis is NI0 where N is an integer. Value of N is: 16