Physics Questions

In the figure the equivalent capacitance between A and B is AO 10 F 10 F HI 16 5 F 1 3 75 F 7 F 3 F 11 6 F HH 6 F 2 5 25 F 1 SE 7 F B

35 A body is moving along a straight line starting from rest with constant power The diagram which correctly represent displacement time s t curve of its motion is S 1 3 S 2 4 S V t

9 A cable that can support a load W is cut into two equal parts The maximum load that can be supported by either part is W a 4 c W b W 2 d 2W

Two identical metal plates are given positive charges and 92 9 respectively If they are now brought close together to form a parallel plate capacitor with capacitance C the potential difference between them is A 91 92 2C B 91 92 C C 91 92 G 00 D 91 92 20 One plate of a capacitor of capacitance 2uF has total charge 10 Cand its other plate has t charge 40 C The potential difference between the plates is in Volt A 7 5 B 15 C 25 D 50

A projectile can have the same range R for two angles of projection If t and to be the times of flights in the two cases then the product of the two time of flights is proportional to 1 R 3 1 R 2005 2 1 R 4 R ti 2usin 0 t2 2usin 90 9 2usin 90 9 2 tit 4 usine coset 2R 9 9

P is a point moving with constant speed 10 m s such that its velocity vector always maintains an angle 60 with line OP as shown in figure O is a fixed point in space The initial distance between O and P is 100 m After what time shall P reach O 1 10 sec 2 15 sec 100m 60 v 10m s 3 20 sec 4 20 3 sec

A tuning fork vibrating with a frequency of 512 Hz is kept close to the open end of a with water as shown in the figure The water level in the tube is gradually lowered When the water level is 17 cm below the open end maximum intensity of sound is heard The room temperature is 20 C Then 17 cm A Speed of sound in air at room temperature is 360 ms B Speed of sound in air at 0 C is 336 ms Tilled Reservoir C If the water in the tube is replaced with mercury then the intensity of reflected sound increases D If the water in the tube is replaced with mercury then the intensity of reflected sound

A particle moving with uniform retardation covers distances 18m 14m and 10m in successive seconds It comes to rest after travelling a further distance of 1 50 m 2x8m 3 12m 4 42m

Vapour is injected at a uniform rate in a closed vessel Wi was initially evacuated The pressure in the vessel UPSEAT 2001 a Increases continuously b Decreases continuously c First increases and then decreases First increases and then becomes constant nts

The magnetic induction in air at a distance d from an isolated point pole of strength m unit will be m a b d c m d md d 3 m d

Current Electricity 12 27 V Find the equivalent resistance between A and B Each resisto has same resistance R b 8 a R 5 c R 5 6 R 5 d R w www 13

17 You are given many resistances capac inductors These are connected to a variable DC voltage source the first two circuits or an AC voltage source of 50 Hz frequency the next three circuits in different ways as shown in Column II When a current I steady state for DC or rms for AC flows through the circuit the corresponding voltage V and V indicated in circuits are related as shown in Column I Column II P V V HH 3 F Column I A 0 V is proportional to B 1 0 V V C V QV V D 1 0 V is proportional to Codes a A p B q C r D st 9 V V vooooo www 6mH 292 oooooo 6mH S r V V oooooo 6mH t V V 000000 6mH V mos 1kQ 292 V HH 3 F V HH 3 F

30 An object is dropped from rest Its velocity versus displacement graph is assume downward direction to be positive L 2 1 2 3 4 S S S

discs of mass in and 4m having radii of a and 2a respectively are rigidly fixed by a massless rigid rod of length 1 24a through their centres This assembly is laid on a firm and flat surface and set rolling without slipping on the surface so that the angular speed about the axis of the rod is wo The angular momentum of the entire assembly about the point O is I see the figure Which of the following statement s is are true JEE Adv 2016 4m O a b m 2a 0 The centre of mass of the assembly rotates about the z axis with an angular speed of co 5 The magnitude of angular momentum of center of mass of the assembly about the point O is 81 ma co c The magnitude of angular momentum of the assembly about its center of mass is 17 ma 2

Target IIT 2 A nonconducting disc having uniform positive charge Q is rotating about its axis with uniform angular velocity oo The magnetic field at the centre of the disc is a directed outward 6 having magnitude c directed inwards Ho Qw 4TR Ho Qw 2 R R 0 Q d having magnitude 5 The coordinates of a particle moving in a plane are given by nt and t b sin pt where a b a and pare 25 Wh a b The rest sum of th In nucle nuclei of c The rest m of the rest o norge d In nucle of a ver SECTI This section cor questions is as appropriate bub OBS have to be

Two large conducting sheets are kept parallel to each other as shown In equilibrium the charge density on facing surfaces is d and o Which of the following may not be electric field at A 1 N A So 0 0 i 5 2 0 1 0 0 i

7 In the given circuit the potential difference across resistance is 80 V and power consumed by it is 160 W If AC frequency is 50 Hz find the value of L 100V 50Hz 1 0 3 H 3 10 H www 2 4 eeeeee L 0 3 H 0 7 H

13 In the figure shown the image of a real object O is formed at point I AB is the principal axis of the mirror the mirror must be A concave placed towards right of I C convex placed towards right of I B concave placed towards left of I D convex placed towards left of I m A

A small block of mass m held compressed against a spring as shown in the figure The spring has force constant of k such that mg k 3m After releasing the block it collides a spheres of same mass which is suspended from a massless rod of length 3m The rod can freely rotated in a vertical circle about its top point Considering the coefficient of restitution 0 5 find the minimum compression in the spring so that sphere can complete full circle l m m k mmmmm

1 K K t ngure 31 12 Figure 31 E30 plates of the capacitor have plate area A and are clamped in the laboratory The dielectric slab is released from rest with a length a inside the capacitor Neglecting any effect of friction or gravity show that the slab will execute periodic motion and find its time period K I 1 1 The 1

extreme position and lowest position are equal The angle 9 of thread deflection in the extreme position will be 1 tan 2 2 tan 2 3 tan 1 2 4 2 tan 1 2

by a 10 Figure 6 W15 shows triang string placed on the two inclined parts of a structure The coefficients of static and kinetic fri are 0 28 and 0 25 respectively at each of the surface Find the minimum and maximum values of m for the system remains at rest b Find the acceleratio either block if m is given the minimum value calcul in the first part and is gently pushed up the inclin a short while m 45 45 Figure 6 W15 2 kg

Point charges 4q q and 4q are kept on the X axis at points x 0 x a and x 2a respectively Then 1988 a b c d only q is in stable equilibrium none of the charges is in equilibrium all the charges are in unstable equilibrium all the charges are in stable equilibrium

is A zero current loop of radius a is placed in a radial field B as shown The net force acting on the loop B 2 Balcos0 1 a 0 C 2 al sine ds D None

33 A force F i 47 acts on block shown The force of friction acting on the block is y a i c 2 4i X 1 kg 0 3 b 1 8 d 3 F

Illustration 5 31 A sliding fit cylindrical body of mass of 1 kg drops vertically down at a constant velocity of 5 cm s 1 Find the viscosity of the oil Strea Oil 14 9 cm 1 kg 15 cm 15 cm

Suppose a tunnel is made in earth which passes through its centre If an object is dropped from R height from earth surface above the tunnel If its 2 R speed at depth from earth surface in tunnel is 2 NGM 12R mass of earth and R is radius of earth then value of N is Given M is

A star which is emitting radiation at a wavelength of 5000 is approaching the earth with a velocity of 1 5 x 10 m s The change in wavelength of the radiation as received on the earth is

out slippi A cylinder of mass m and radius R is rolling horizontal surface with angular velocity oo The velocity of centre of mass of cylinder is woR The cylinder comes across a step of height R 4 Assume required friction is present at edge of the step Answer the following questione hased on abou 13 A Find the minimum angular velocity wo of cylinder so that cylinder rides up the step without slipping or jumping 2 3g 5 VR 5 3g 2VR C B D 3 3g 5VR o R g 3R R 4

Example 14 A point charge q is placed on the top of a cone of semi vertex angle 0 Show that the electric flux through the base of the cone is q 1 cos 0 280 HOW TO PROCEED This problem can be solved by the method of symmetry Consider a Gaussian surface a sphere with its centre at the top and radius the slant length of the cone The flux through the whole sphere is qleo Therefore the flux through the base of the cone can be calculated by using the following formula S So Here So area of whole sphere Pe H q E0

23 A solid conducting sphere of radius a has a net positive charge 2Q A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge Q The surface charge density on the inner and outer surfaces of the spherical shell will be a c 0 2Q Q 2 4 b 4 c Q 4TC 2 C b Q Q 2 4 b 4 c 2 d None of these b

A car has to cover the distance 60 km If half of the total time it travels with speed 80 kmh and in rest half time its speed becomes 40 kmh 1 the average speed of car will be a 60 kmh 1 b 80kmh 1 c 120 kmh 1 d 180 kmh

4 Zero A point mass m is placed at a distance R from the surface of a solid sphere of mass m and radius R The gravitational potential energy of this system of point mass and sphere is 1 2 Gm 28 2 2 Gm R

Choose the correct statement following 1 Dimensionless quantities can have a unit 2 A dimensionally correct equation must be correct 3 Change in system of units will surely change the numerical value of the physical quantity 4 Dimensions of a physical quantity can never be a fraction

Two masses are executing SHM under influence of a vertical spring as shown with an amplitude of 2 cm and angular frequency of 5 rad s When the extension of spring is maximum suddenly the string breaks and 3 kg mass falls off What is the maximum velocity of the 1 kg mass in cm s during subsequent motion 1 320 3 225 m 1 kg m 3 kg 2 175 4 288

ar A solid current carrying conductor of radius R is having current per unit area J as J constant and r is distance from axis Find magnetic field at distance x from axis of wire Assume x R where a is a R 3 Mo ax 3R Mo ax 2 ax 2R 4 Zero

7 A solenoid of length 20 cm area of cross section 40 cm and having 4000 turns is placed inside another solenoid of 2000 turns having a cross sectional area 8 0 cm and length 10 cm Find the mutual inductance between the solenoids Ho 200 of nodius R and having

Aakash Rank Boost 1 An ideal monoatomic gas is carried around the cycle ABCDA as shown The efficiency of the gas cycle is PA 3P 1 1 2 Po 4 www 21 3 6 A Va C D 2 V

A weight of 200 kg is repeatedly dropped freely from a height of 10 m on the head of a pole of mass 50 kg to push it into the ground For every impact the pole penetrates 7 cm into the ground Find the average resistance of the ground Ans 223 440 NI

is col Q 7 they are exactly out of phase and the interferen 4 A travelling wave at a rigid boundary or a closed end is reflected with a phase reversal but the reflection at an open boundary takes place without any phase change For an incident wave acos wel a cosciutto y x t a sin kx wt the reflected wave at a rigid boundary is y x t a sin kx wt For reflection at an open boundary y x t a sin kx wt 1 2 cos a cos uteg 2 kn wt 2 oring in opposite directions produces standing

4 A disc of mass m and radius R is hinged at its centre A light string is wrapped on its rim and the free end of the string is being pulled by a force F Assuming that the string does not slip over the disc the acceleration of free end the string is R mass m F pode muinsmon

1 the wave intensity remains constant for a plane wave 2 the wave intensity decreases as the inverse square of the distance from the source for a spheric wave 3 the wave intensity decreases as the inverse of the distance from a line source total power of the spherical wave over the spherical surface centered at the source remai constant at all the times

24 When a pressure of 100 atm is applied on a spherical ball then its volume reduces to 0 01 The bulk modulus of the material of the rubber in dyne cm2 a 10 10 b 100 10 2 c 1 x 10 2 d 20 10

A small ball thrown at an initial velocity u directed at an angle 0 37 above the horizontal collides inelastically e 1 4 with a vertical massive wall moving with a uniform horizontal velocity u 5 towards ball After collision with the wall the ball returns to the point from where it was thrown Neglect friction between ball and wall The time t from beginning of motion of the ball till the moment of its impact with the wall is tan37 3 4 3u 181 A B C 5g 5411 125g D 25g 5411 25g

36 If A 21 31 and B 41 61 2k then the angle between A and B is a 45 c 000 b 690 d none

1 Consider a solid sphere of radius r and mass m which has a charge q distributed uniformly over its volume The sphere is rotated about a diameter with an angular speed o Show that the magnetic moment u and the angular momentum 1 of the sphere are related as q 2m 1

A container has a lid held in place by a spring as shown in figure Two moles of ideal mono atomic gas is kept inside the container having cross section area 100 cm at 300 K at atmospheric pressure 10 Pa The spring exerts a force of 1000 N when the lid is in place The maximum amount of heat that can be given to the gas so that gas does not escape from the container Assume heat capacity of the spring and container to be negligible R universal gas constant in SI units T 300K Ag P 105 pa 100 A F 1000N AU W W PAV W2NRAT ZAX 1000 P B 000 P I eeeeee C1500 B g nC AT n Cv R n 2 8 Cp s D 600 R

For a particle in uniform circular motion the acceleration a at a point P R 0 on the circle of radius R is Here 0 is measured from the x axis 1 2 3 4 R i cos0i sin 0j R R R R sin 0i V cosei cos Oj R sin Oj

102 A R R 1552 il A B B D D C R 1052 C m 532 5 Determine electric potential at each of the four nodes ABCD in the circuit Point Electric Potential V M 30V Battery R 2012 6 Determine the net current flow into AND out of each of the four nodes ABCD in the circuit out Point In 3 2 37A 2 36A 1 56A 1 56A 2 37A2 37A 92A 93A 7 Determine the net voltage drop around at least three of the six or so closed loops STION Uco your experimental results to analyze the circuit you built in terms of

4 A thin uniform wire is bent to form the two equal sides AB and AC of triangle ABC where AB AC 5 cm The third side BC of length 6cm is made from uniform wire of twice the linear mass density of the first The distance of centre of mass from A is 34 11 34 11 34 9 A cm B cm C cm D 11 45 cm