Basic Physics Questions and Answers

8 Calculate the magnetic moment of a thin wire with a current I 0 8A wound tightly on half a tore The diameter of the cross section of the tore is equal to d 5 0 cm the number of turns is N 500 in Am

In Young s double slit interference experiment the distance between slits and screen is made 1 6 times initial value by keeping all other parameters same Final band width will be times initial value CO2 O 4 8 O 1 6 O 0 625 O 3 2

A man running along a straight road with a uniform velocity u ui feels that the rain is falling vertically downwards along If he doubles his speed he finds that rain is coming at an angle 8 with the vertical The velocity of the rain with respect to the ground is A ui u tan 0 B ui u C u i tane tane D u i tane i

1 E E 3Eb 2 Ea 3Eb 3 Ea E 3Eb 35 4 Ea 3E E 0 36 37 38 Atomic binding energy of elements A and B are Ea and Eb respectively Three atoms of B form one atom of A In this fusion process E energy is released the relation between Ea E and E Question Type Single Correct Type English 39 38 39 40 Review Q

27 Which of the following is not an application of conservation of linear momentum While firing a bullet the gun must be held tight to the shoulder b When a man jumps from a boat to the shore A rocket explodes on midway from the ground A body suspended from the hook of a spring balanced in a lift which is accelerated downward

4 A body of mass 20 kg starts from rest at the top of a hill of height 50 m and moves down the rough curved track If its speed at the bottom is 30ms the work done by friction is g 10ms 1 10 000 T 2 1000 50 m 2 1001 4 10 1

A particle moves along the x axis so that at time t 0 its position is given by x t 2t3 312 36t 50 What is the total distance travelled by the particle over the time interval 0 t 5 90 145 195 50

Two objects of the same mass slide down on two different smooth inclined plane of same height but of different angles When they reach the bottom then 1 and 1 are the impulses of the weights of the first and the second object during the motion P and P2 are the powers developed by the weights of the first and the second objects sina2 sin 1 C sina 12 sin 2 A D R 2R 4 1 B 063 P sina P2 sina Hey

1 1 20 min A body cools from 60 C to 40 C in 10 minutes If the room temperature is 10 C and assuming Newton s cooling law holds good find the time taken to cools from 40 C to 20 C Question Type Single Correct Type 2 30 min 3 40 min English 4 50 min Review

27 Following figure shows the variation of velocity with time for an object Determine the displacement of the object during the 16 seconds Also find the acceleration of the object during the time interval 10 to 14 seconds v m s 10 t s 2 4 6 8 10 12 14

Body of mass M is kept on a rough horizontal surface having coefficient of friction u Person is trying to pull the body by applying an external force horizontally but the body is not moving The force by the surface on A is F then A F Mg 2 C Mg F Mg 1 B F Mg D Mg F Mg 1 2 efficient of friction between the block and

6 The charge flowing in a conductor varies with time as Q at bt2 Then the curre decreases linearly with time reaches a maximum and then decreases falls to zero after a time period t 3a 2b changes at a rate 2b

11 Two electric bulbs A and B are designed for the same voltage Their power ratings are PA 500W and PB 400W respectively with PA PB If they are joined in series across a 300 Volt supply A will draw more power than B B will draw more power than A the ratio of powers drawn by them will depend on V A and B will draw the same nowor

A ladder of mass m and length I stands against a frictionless wall with its feet on a frictionless floor If it is let go at an initial angle 80 60 then the angle 0 at which the ladder loses contact with the wall is given as sin 1 N find N 1

zero XO A block accelerates down a slope as shown in the figure The upper portion of the slope is smooth and lower portion is rough On the lower portion d A Rough Smooth 0 i the speed of the block may decrease or remain same ii the acceleration of block reduces iii the forces are balanced Sonsti Which of the following is are correct a Only i c ii and iii b i and ii d i ii and iii

8 In the given diagram the reading of the ammeter is when the internal resistance of the battery is zero 402 1 40 29 A Hint PD across 502 is 10 V www 2 10 9 A www 502 3 5 3 A T10 V 4 2 A

An electric spark jumps along a straight line of length L 10 m emitting a pulse of sound that travels radially outward from the spark The spark is said to be a line source of sound The power of this acoustic emission is P 1 6 x 104 W a What is the intensity I of the sound when it reaches a distance r 12 m from the spark b At what time rate PA is sound energy intercepted by an acoustic detector of area Ad 2 0cm aimed at the spark and located a distance r 12 m from the spark

One conducting U tube can slide inside another as shown in figure maintaining electrical contacts between the tubes The magnetic field B is perpendicular to the plane of the figure If each tube moves towards the other at a constant speed v then the emf induced in the circuit in terms of B I and v where I is the width of each tube will be a Bl v b Bly c zero D d 2 BL

The quantity of electricity required to reduce 12 3 g of nitro benzene to aniline assuming 50 current effeciency is in 1 115800 C 3 231600 C Abne 2 57900 C 4 28950 C

During the electrolysis of water 4 mol of electrons were transferred from anode to cathode The tota volume of gases produced at STP will be approximately 1 67 2 L 3 44 8 L 2 22 4 L 1 O

where m is the mass of 1 A quantity X is given by electron e is the charge of electron is the permittivity of free space c is the velocity of light and h is the Planck s constant The dimensional formula for X is the same as that of a length c velocity 8ech 3 b frequency d wave number

5 Calculate simple interest and compound interest assuming that principal amount is 10 000 interest rate is 9 for three years What is the amount different between compound and simple interest 3M

Find the ratio of least separation between two points to be distinguished for same objective by a microscope for light of wavelength 5000 and electrons accelerated through 100 V used as illuminating substance 1250 4075 2500 1875

Four capacitors each of capacitance C are connected as shown in the figure The ratio of capacitance between P and R to the capacitance between P and Q is C P 01 1 3 4 2 3 C C R

The height of a cylindert s decreasing at a constant rate of 4 cm per second The volume remains a constant 17 cubic cm At the instant when the radius of the cylinder is 1 cm what is the rate of change of the radius 0 796 cm s 0 875 cm s 0 670 cm s 0 456 cm s

5 A force acts on a 2 kg object so that its position is given as a function of time as x 31 5 What is the work done by this force in first 5 seconds a 850J b 950 J c 875 J d 900 J LIFF Main

S and S are two slits in horizontal fixed plane on which light of wavelength 6000 A is incident d 1 mm D 1 0 m O is the origin of the coordinate system At t 0 the screen is released g 10m s Se Sv fer af en af d 1 mm D 1 0 m g 10m s Find the velocity of central maxima at t 4 sec 4 sec 1 40 m s D R6000 D 1 2gt 2 80 m s S 3 40 2 m s v gt Mo y S 6000 M 4 80 2 m s

as shown in figure the distance travelled by the car in the 25s is A 750 m B 875 m C 500 m D 975 m The acceleration of a car started at 1 0 varies with time as shown in figure the distance travelled by the car in the 25 vis Aj 750 m B 875 m C 500 m D 975 m

16 An 80 6 nucleus is spherical having radius R surface area A and volume V According to empirical observations the volume of the so Sn 28 nucleus assumed to be spherical is V radius R and surface area A Then A R 8R C V 8V B A 8A D R 2R

A parallel circuit consists of the two ideal inductances L and 2L and a resistance R as shown At t 0 the same current 101 is flowing in both the inductances in the same direction Then choose the correct option s LI A The energy stored in inductance L in steady state is 18 B The energy stored inductance 2L in steady state is zero C The net heat dissipated in the resistor is 3L13 2 4 The net heat dissipated in the resistor is L 3 L eeeeeee 21 0000000 93 dii Jd at e

A fully charged capacitor C with intial charge qo is connected to a coil of self inductance L at t 0 The time at which the energy is stored equally between the electric and the magnetic fields is 1 2T LC 2 VLC 3 TV LC 4 TU VLC

9 Two capillary tubes A and B are immersed in water One is straight and the other is in the form of a rectangular U tube as shown in figure The tube A is sufficiently long The lower end of the bent tube is at depth H Then there will be no flow of water from tube B is P 2 2 1 H h 3 H 0 A B H 2 0 H h 4 All of these

Two bodies A and B masses 10 kg and 15 kg 36 respectively kept on a smooth horizontal surface are tied to the ends of a light string If T represents the tension in the string when a horizontal force F 500 N is applied to A as shown in figure 1 and T be the tension when it is applied to B figure 2 then which of the following is true 10 kg A F 500 N 10 kg 1 T T 500 N 2 T T 250 N 3 T 200 N T 300 N 4 T 300 N T 200 N 15 kg B 15 kg B F 500 N 10 kg a 15 kg a fe f in I F 500 Na F 500 N 2 1 10 kg A 10 kg 1 T T 500 N 2 T T 250 N 3 T 200 N T 300 N 4 T 300 N T 200 N 15 kg B 15 kg B F

In a lab experiment with standing sound waves the sound with the frequency 1200Hz generated a resonance in a tube open on one side closed on the other when the tube length was set to 65 0 cm 78 5 cm and 94 0 cm but no lengths between What sound velocity in the air indicated the measurements Do not forget the estimate of the margins of error

Three blocks of identical masses are connected by 29 41 CH strings as shown The whole system is accelerated to the right on a frictionless horizontal surface by a horizontal force F The net force acting on the middle block is 1 zero 3 2F 3 2 F 4 F 3 fed f cata fara sa 1 3 2F 3 2 F 4 FA

4 1200 N Frictional force on the 2 kg block is 1 5 N 2 zero 3 2 5 N 4 5 3N In 2kg 30 0 5 1kg 38 4 2 1200 N 1 5 N 2 zero 3 2 5 N 4 5 3N 2kg H 0 5 30 III WY 11

1 A body released from height h takes time t to reach the ground After time t 2 its height from the ground is h 3h h 3 h A B 4 2 Which of the following is correct A Distance 2 Displacement 21 Distance Displacement D B C Both A B D None

Two satellites are in different circular orbits around a planet with speeds in ratio 1 2 One satellite does an amount of work on the other satellite resulting in both satellites moving in the same circular orbit midway between the two earlier orbits What is the ratio of their masses larger smaller

The amplitude of upper and lower side bands of A M wave where a carrier signal with frequency 11 21 MHz peak voltage 15 V is amplitude modulated by a 7 7 kHz sine wave of 5V amplitude are Vand V respectively Then the value of is a 10 10

ctron mass A small concentration of minority carriers is injected into a homogeneous semiconductor held at 300K An electric field of 30 V cm is applied across a distance of 1 5 cm in a time of 300 us We width of the crystal As a result the minority carriers move s is the diffusion coefficient of the minority carriers in the semiconductor

A particle of mass m is moving along a circle of radius r At some instant its speed is v and it is gaining speed at a uniform rate a then at the given instant acceleration of the mparticle is

A magnet of length 14 cm and magnetic u is broken into two parts of length 6 cm and 8 cm They are put at right angle to each other with opposite poles together The magnetic dipole moment of the combination is Answer Rate this questic

3 Tom and Jerry are placed at a distance of 32 cm Between them a convex lens is placed having a focal length of 15 cm in such a way that images of both Tom and Jerry are formed at the same place What can be the possible distance of Tom from the lens

The angles which the vector A 31 61 2k 5 makes with the cordinate axis 1 cos 1 2 cos 3 cos 1 4 None of these COS cos cos 4 7 005 TA 31 6j 2k ART 1 cos 1 2 cos 3 cos 1 4 Cos I COS COS I

Moment of inertia of a uniform hexagonal plate about an axis LL is T as shown in the figur a If the moment of inertia about axis XX of an equilateral uniform triangular plate of 13 imes density as hexagon is I a Find the value of a Ph L L Figure a PL X i Figure h 2 Kma Iday

In the given figure if i 3 sin wt and i2 4 cos wt then i3 is i Question Type Single Correct Type 1 2 3 5 sin wt 53 5 sin wt 37 5 sin wt 45 H 3

14 A bullet of mass 50 g moving horizontally with a velocity of 400 m s strikes to a block of mass 20 kg placed on a smooth horizontal surface and rebounds back with same speed Then average force acting on the block if the time of interaction is 0 05 second is 2 1600 N 4 800 N 1 400 N 3 200 N 50 g af eft 400 m s fax fa in cu yffer la f 1 400 N 3 200 N 2 1600 4 800

3 tan 4 tan A B If A 31 21 and B 21 31 k then find 3 unit vector along A B 1 3 i j k 3 i j k 3 2 j k 3 i j k 3 3 tan af A 31 21 am A B 1 3 i j k 3 i j k i j 3

What is the angle between A and the resultant of 2 A B and A B 1 0 3 tan 1 B 2 tan 4 tan 1 B A B A B Efe A B f 1 0 3 tan

The coefficient of static friction between contact surfaces of two bodies is 1 The contact surfaces of one body support the other till the inclination is less than 1 30 3 60 2 45 4 90 X