Physics Questions

instantaneous picture of a longitudinal harmonic wave travelling along the negative x axis Identify the correct statement s related to the movement of the points shown in the figure un vp v d mink YA a A a C f V b C e h g k The points moving in the direction of wave are A b B c C f D i X The points moving opposite to the direction of propagation are B d D j The stationary points are A a C g T B c D k The points of maximum compression are A c B g D k

60 A ball of radius r rolls inside a hemispherical shell of radius R It is released from rest from point A as shown in figure The angular velocity of centre of the ball in position B about the centre of the shell is A

In the figure shown rod AB is light and rigid while rod CD is also rigid and hinged at midpoint O Rod can rotate without friction about O The time period of small oscillation of rod CD is T 2 Where m is mass of rod CD and k is spring constant of each spring The value of n is m nk A k eeeeeeeeee C heeeeeeeeee k reeeeeeeeeer k B O

and the acceleration of the 500 g block in figure 5 E18 100 g 50 g 30 0 Figure 5 E18 500 g

2 In an astronomical telescope in normal adjustment a straight black line of length L is drawn on inside part of objective lens The eye piece forms a real image of this line The length of this image is I The magnification of the telescope is 1 2 1 3 1 4 L I L I

D A mass m moving horizontally along the x axis with velocity v collides and sticks to a mass of 3m moving vertically upward along the y axis with velocity 2v The final velocity of the combination is AIPMT Mains 2012 1 3v v 3 3 2 12 1v 1 1 0 4 1 2

3 3 4 4 40 The equation y 4 2 sin 6t 3x represents wave motion with 1 amplitude 6 units 2 amplitude 4 units 3 wave speed 2 units 4 wave speed 1 2 units

For the circuit shown in figure the potential difference between points a and b is 2V 1 2 4 V 3 2 V 102 www 192 www www 192 452 T4V b ww 12 2V 2 2 8 V 4 3 2 V

5 A proton and deuteron are accelerated by same potential difference and enter in region of uniform electric field in direction perpendicular to it The deflection of proton is 1 Equal to deflection of deuteron 2 More than deflection of deuteron 3 Less than deflection of deuteron 4 May be more or less than deflection of

16 For a ferromagnetic substance the correct graph between X and H is Xm 1 3 Xm R H xm H 2 4 12m H H

In the following transistor amplifier circuit B 50 VCE of the transistor is 245kQ 40 AY B 10 V 2ks

5 Prism angle of glass prism is 10 It s refractive index of red and violet colour is 1 51 and 1 52 respectively Then its dispersive power will be 1 0 015 2 0 020 3 0 011 4 0 019

Let m 1 kg m 2 kg and m 3 kg in figure 5 E12 Find the accelerations of m m and m The string from the upper pulley to m is 20 cm when the system is released from rest How long will it take before m strikes the pulley

Example 3 54 Figure shows three identical bulbs A B and C which are connected to a battery of supply voltage V When the switch S is closed then discuss the change in A B C lo gaite V S i the illumination of the three bulbs ii the power dissipated in the circuit

3 6 5 A man of 50 kg mass is standing in a gr space at a height of 10 m above the floor H throws a stone of 0 5 kg mass downwards with speed 2 m s When the stone reaches the flo the distance of the man above the floor will be 1 20 m 3 10 1 m kg Best 2 9 9 m 4 10 m JON C

Example 10 12 Distance between the slits in YDSE shown in figure is d 20 where is the wavelength of light used Fir the angle 0 where 1 2 45 d 0 i central maxima where path difference is zero is obtained ii thi

The motion of a particle of mass m is gl x 0 fort 0 s x t A sin 4 t for 0 t 1 4 s A 0 and x 0 for t 1 4 s Which of the following statements is true a The force at t 1 8 s on the particle is 16 T Am b The particle is acted upon by an impulse of magnitude 4 r A m at t 0 s and t 1 4 s c The particle is not acted upon by any force d The particle is not acted upon by a constant force e There is no impulse acting on the particle

6 An ice cube contains a large air bubble The cube is floating on the horizontal surface of water contained in a trough What will happen to the water level when the cube melts 1 It will remain unchanged 2 It will fall 3 It will rise 4 First it will fall and then rise

4 35 A rod of length with thermally insulated lateral surface and cross sectional area A consists of material whose heat conductivity coefficient varies with temperature as k a T where a is a constant The ends of the rod are kept at temperatures T and T T T Find the function 7 x where x is the distance from the end whose temperature is T and the heat flow density 2 2 Ans T x T T T q a l In T T

51 A thin rod AB of length is kept vertical on a horizontal floor such that end A is in contact with floor If the rod is allowed to fall without slipping at end A then its angular velocity just before hitting the ground is 1 3gl 3 lal 2 2 gl 4 2g

For a particle executing simple harmonic motion the KE is given by K K cos wt Then maximum value of potential energy for given particle 1 May be K 2 Must be K 3 May be less than K 4 Roth 1 3

The value of can be B me obtained by using a specially designed vacuum tube The figure contains a heated filament F and an anode A which is maintained at a positive potential relative to the filament by a battery of known voltage v Electrons get emitted from the heated filament and are accelerated towards the anode which has a small hole in the centre for the electrons to pass through into a region of constant magnetic field B which points into the plain of the paper The electrons then move in a semicircle of diameter d hitting the detector cathode as A F

In a simple pendulum length increases by 4 and g increases by 2 then time period of simple pendulum 1 Increases by 4 2 Increases by 3 3 Decreases by 3 4 Increases by 1

the ball If yes what should be the angle A yes 60 B yes 30 C no D yes 45 The relation between time t and distance x is t ax bx where a and b are constants The acceleration is AIEEE 2005 A 2abv B 2bv C 2av D 2av it the rate of through a distance S then continues at constant speed for orced is 15 S then

d it The piston cylinder arrangement shown contains a diatomic gas at temperature 300 K The cross sectional area of the cylinder is1 m Initially the height of the piston above the base of the cylinder is 1 m The temperature is now raised to 400 K at constant pressure Find the new height of the piston above the base of the cylinder If the piston is now brought back to its original height without any heat loss find the new equilibrium temperature of the gas You can leave the answer in fraction DEF 20041 im

resistance between the ends of a face diagonal such as a and c a h IL X C C of

c A B a 59 A is directed along north and B is directed south west If C A B then which of the follow relations are correct a C must be equal to A B b C must be greater than A B c C must be greater than A B 0 C al

A ball floats on the surface of water in a container exposed to the atmosphere If the container is now covered and the air is pumped out then A the ball will remain at its former depth B the ball will rise somewhat C the ball will sink to the bottom D the ball will sink a bit

A wheel of mass M rotating on a vertical plane can roll down an incline of inclination Prove that if a body of mass m is attached to its circumference the wheel will remain in equilibrium if sin m m M

21 The centres of two identical small conducting spheres are 1 m apart They carry charges of opposite kind and attract each other with a force F When they are connected by a conducting thin wire they repel each other with a force F 3 What is the ratio of magnitude of charges carried by the spheres initially a 1 1 b 2 1 d 4 1 c 3 1

5 In the above problem If the force F would have been applied on the bar of mass m then what would have been the maximum force F for no slipping of m of M The horizontal surface on which the plank is kept is smooth l E M

The potential at point P is k V V d A C kV 2V k 2 B D kV V K 1 kV 2V k 2 V 2d K P

48 The position vector of a particle varies with time as r ro 1 at t where ro is a constant vector a is a positive constant then the distance covered during the time interval in which particle returns to its initial position is V ro 1 2a1 a To a b To 2a c d ro 2 ro To a 200 C fut 120 sell 0 no 1 2at te be E 15 2 1 20 E so val Ay

Which of the following statements are correct a Centre of mass of a body always coincides with the centre of gravity of the body b Centre of mass of a body is the point at which the total gravitational torque on the body is 100 zero c A couple on a body produce both translational and rotational motion in a body d Mechanical advantage greater than one means that small effort can be used to lift a large load NEET 2017 1 b and d 3 b and c 2 a and b 4 c and d about

14 A child AB is star straight plane mirror fixed to a vertical wall His father CD is standing behind him as shown in the fig The height of the father is double the height of the child What is the minimum length of the mirror required so that the child can completely see his own image and his father s image in the mirror Given that the height of father is 2H Assume eye level at the top most point D C A B H H wall 12

20 An insect fly start from one corner of a cubical room and reaches at diagonally opposite corner The magnitude of displacement of the insect is 40 v3 ft Find the volume of cube a 64 3 ft b 1600 ft c 64000 ft d none of these 1 In above problem if the insect does not fly but crawls What is the minimum distance travelled by the insect a 89 44 ft c 40 ft b 95 44 ft d 80 ft

The driver of a bus travelling with a speed v suddenly observes a wall in front of his bus at a distance a Father of this driver who was also a driver had advised him to take a circular turn to avoid hitting in such a situation However the driver in question decides otherwise by using his own wisdom He applies brakes as hard as possible without taking a circular turn then 1 he is more likely to hit the wall 2 he is less likely to hit the wall 3 he is as likely to hit the wall 4 none of the above

A rod lies along the x axis with one end at the origin and the other at x o It carries a uniform charge AC m The electric field at the point x a on the axis will be AMU Med 2012 2 4 a E c 2 4 2 2 b E 2 d E 2

Four square pieces of insulation are available to cover an opening area 2A They are of different materials with conductivities K and K as shown and arranged as shown for case I and case II They are of same thickness and area A Find the correct option to ensure lesser heat flow K K K K Case I O Case Il O Case 1 O Equal heat flow O Unpredictable K K K K Case Il

llustration 18 A simple pendulum of length l is made to oscillate with a solid sphere density D in a non viscous fluid of density p find the period of oscillation D pl

Example 14 A toy rocket of mass 0 1 kg has a small fuel of mass 0 02 kg which it burns out in 3 s Starting from rest on a horizontal smooth track it gets a speed of 20 ms after the fuel is burnt out What is the approximate thrust of the rocket What is the energy content per unit mass of the fuel Ignore the small mass variation of the rocket during fuel burning NCERT

tration 2 An electron gun G emits electrons of energy 2 keV travelling in the positive x direction The electrons are required to hit the spot S where GS 0 1 m and the line GS makes an angle of 60 with the x axis as shown A uniform magnetic field B parallel to GS exists in the region outside the electron gun Find the minimum value of B needed to make the electrons hit S 60 60 S v cos 60 V v sin 60

84 From a point on the ground a particle is projected with initial velocity u such that its horizontal range is maximum The magnitude of average velocity during its ascent is 1 5u 2 2 5u 2 2 3 5u 2 2 4 u 5 85 The velocity of projectile at the point of projection is 21 31 m s The velocity at a point where the projectile reaches is 1 21 31 m s 2 21 31 m s

A toroid is having 100 turns inner radius 9 cm and outer radius 11 cm then its self inductance is 1 2 H 2 Ho 2 3 Ho 5 4 5 Ho

questions 1 Discuss the different types of motion with examples 2 Differentiate between scalar and vector quantities 3 How is the weight of an object measured Numerical questions 1 A shark swims due East for a distance of 8 9 km turns around and goes due West for 2 8 and finally turns around again and heads 5 7 km due East a What is the total distance travelled by the shark b What is the displacement of the shark Ans a 17 4 km b 11 8 km 2 What is the average speed of a cheetah that sprints 100 m in 4 s What if it sprints 50 m in 2s Ans 25 m s 25 m s

ABCDEF is a regular hexagon with point O as center The value of AB AC AD AE AF Pis 1 2AO 2 4AO 3 6AO 4 0

A particle P is moving in a circle of radius r with uniform speed v C is the centre of the circle and AB is diameter The angular velocity of P about A and C is in the ratio 1 4 1 3 1 2 2 2 1 4 1 1

8 A thick rope of rubber of length 8 m and density 1 5 10 kg m has Young s modulus 3 5x 106 Nm 2 When hung from ceiling of a room the increase in length due to its own weight is a 96 10 3 m b 19 2x 10 5 m c 9 4 cm d 9 6 mm

Spring constant of the spring in the figure shown is 100 N m If system released slowly then elongation in the spring is approximately g 10 m s 49 Fc 1 26 cm 3 6 cm 2 kg 4 kg 2 13 cm 4 20 cm O K 100 4x10 2 adax a 4x 41 T 20 CU nga

7 In the circuit shown in figure charge stored in the capacito of capacitance 5 F is HHHHHH 2 F 2 F 2 F 5 F 3 F 4 F a 20 C b zero tr 100 V c 60 C d 30 C