Basic Physics Questions and Answers

A swimmer crosses a rive of width d flowing at velocity v While swimming he heads himself always at an angle of 120 with the river flow and on reaching the other end he finds a drift of d 2 in the direction of flow of river The speed of the swimmer with respect to the river is 1 2 3 v 3 4 2 3 v 2 2 2 3 v 4 2 3 v

SolveLancer Test What is the resistance offered by a capacitor and an inductor to a 12 V DC supply at steady state SolveLancer Test b a Infinite by capacitor and Zero by inductor Zero by capacitor and Infinite by inductor It will vary depending upon the value of capacitor and inductor c d Cannot be determined

1 A particle of mass 2 kg is moving in circular path with constant speed 20 m s The magnitude of change in velc when particle travels from A to P will be f P V 1 20 2 m s 3 40 2 m s A particle is in uniform circular motion then its volonitui 2 40 m s 4 Zero

11 The minimum magnifying power of a telescope is 100 If the focal length of eye piece becomes one third the minimum magnifying power will becomes 1 300 2 100 3 3 100 3 4 900

The work done by gravity exerting an acceleration of 10 m s for a 10 kg block down 5 m from its original position with no initial velocity is grav mass x acceleration and W F x dx 1 250 J 2 500 J 3 100 J 4 1000 J

2 38 A dancer leaps off the floor with her centre of mass having a velocity of 5 m s making an angle of 0 37 to the horizontal At the top of the trajectory the dancer has her legs stretched so that the centre of mass gets closer to head by a vertical distance of 0 25 m By how much does the head rises vertically from its initial position sin 37 3 5 G

Impulse due to a force on a body is given by I fFdt If the force applied on a body is given as a function of time t as F3t 2t 31 2t 5 N 5 N then impulse on the body between t 3 sec to t 5 sec is 1 175 kg m sec 2 41 kg m sec 3 216 kg m sec 4 124 kg m sec

Ray Optics and Optical Instruments 34 For the given figure the possible value of for which image is formed on the right of sphere at a distance R from the sphere is 1 1 5 3 2 object O R R 2 1 33 4 2 5

The profit function for a product is given by P x x 3 4x 2 400x 1200 where x is the number of units produced and sold and P is in hundreds of dollars Use factoring by grouping to find the numbers of units that will give a profit of 40 000 The numbers of units that will give a profit of 40 000 are Type an integer or a fraction Use a comma to separate answers as needed

Q4 For the circuit shown in Fig below determine the current through RL when its value is 50 2 Find the value of RL for which the power drawn from the source is maximum 10 w 50V www 20 ww 15 15 M 30 M R

ne of these 81 An astronomical telescope has an angular magnification of magnitude 5 for distant objects The focal length of objective and the eye piece are 30 cm and 6 cm respectively Then the length of the tube of telescope will be 1 36 cm 3 5 cm 32 The distance between an obiect 2 30 cm 4 150 cm gram 87 speec 1 5 3 1 In a follow devia 1 8

Aakash Institute 5 Spherical aberration in a thin lens can be reduced by 1 Using monochromatic light 2 Using a doublet combination 3 Using a circular annular mask over the lens 4 Increasing the size of lens

If A 2i 4j 5k the direction cosines of the vector A are 8 22 direction cosines or directional cosines of a vector are the cosines of the angles between the vector and the three ve coordinate axes 4 1 2 3 4 2 45 T 11 4 45 3 1 45 2 45 and 2 45 and 0 and 5 45 and 3 45 4 45 5 45

Aakash Institute 73 A convex lens makes a real image 4 cm long on a screen When the lens is shifted to a new position without disturbing the object or the screen we again get a real image on the screen which is 9cm long The length of object must be 1 2 25 cm 2 6 cm

he radioactive isotope of hydrogen is H 2 H 3 H 4 H Solution In dinoflagellates cells are generally covered by a rigid coat theca or lorica of articulated and sculptured plates formed of cellulose because of which these protists are often known as armoured dinoflagellates Hence option c Albugo Saccharomyces is

Three separate segments of equal area A A2 and A3 are shown in the energy distribution curve of a blackbody radiation If n n and n3 are number of photons emitted per unit time corresponding to each area segment respectively then E OOOO A A N2 N1 N3 N3 N1 N n n Nz N3 N2 N1 A D

76 A small pin fixed on a table top is viewed from above from a distance of 50cm By what distance would the pin appear to be raised if it is viewed from the same point through a 15cm thick glass slab 3 held parallel to table R I of glass 1 15cm 3 5cm 2 10cm 4 35cm

d 20 cm The focal length of a simple convex lens used as a magnifier is 10 cm For the image to be formed at a distance of distinct vision D 25 cm the object must be placed away from the lens at a distance of MP PET 2008 a 0 5 cm c 7 20 cm b 7 14 cm d 16 16 cm

If a collision takes place between A and B and the coefficient of restitution is c 0 5 what is the magnitude of the x and y components of the velocity of A after the impact in m s Motion is confined to the x y plane O a Vx 1 321 Vy 1 526 Ob Vx 1 294 Vy 1 532 OC VX 1 551 Vy 1 667 d VX 1 732 Vy 1 528 e VX 1 421 Vy 1 432 10 kg 45 A 12 kg A 3 m s 30 20

The displacement of particle is zero at t 0 and at t t it i x It starts moving in the x direction with velocity which varies as v k x where k is constant The velocity 1 varies with time 2 is independent to time 3 inversely proportional to time 4 inversely proportional to acceleration

An achromatic convergent lens of focal length 20 cm is made of two lenses in contact of materials having dispersive powers in the ratio of 1 2 and having focal lengths f and f respectively Which of the following is true 1 f 10 cm f 20 cm 2 f 20 cm f 10 cm 3 f 10 cm f 20 cm 4 f 20 cm fa 10 cm

kash Institute 3 For an astronomical telescope magnification produced in normal adjustment is 10 and length of telescope is 1 1m The magnification produced when image formed at least distance of distinct vision is 1 14 2 18

The volume flow rate of water flowing out of a tubewell 3t 4t 1 m sec What will be the volume of water flown out of the tubewell in the 3rd dv is given by Q sec if the volume flow rate is defined as Q dt 1 10 m 2 17 m 3 3 36 m 3 4 34 m 3

Two spheres P and Q of equal radii have densities p and p2 respectively The spheres are connecte by a massless string and placed in liquids L and L2 of densities 1 and 2 and viscosities and respectively They float in equilibrium with the sphere P in L and Q in L2 and the string being tau If sphere P alone in L has terminal velocity up and Q alone in L has terminal velocity vo then a b 41 as de r 71 12 4 L2 P Q

At STP a rod is hung from a frame as shown in figure leaving a small gap between the rod and floor The frame and rod system is heated uniformly upto 350 K Then 2 If 1 The rod will never touch the floor in any case then rod may touch the floor then rod may touch the floor a rod frame rod frame 3 If a a frame 4 None of the above Rod

a photoelectric experiment the stopping potential V versus applied frequency v graph for three different metals A B C are as shown The metal with maximum threshold wavelength is V M A 3 C ABC 2 B 4 All have same values

Four vectors A B C D all have the same magnitude and lie in a plane The angle between adjacent vectors is 45 as shown Which of the following equation is are correct A A C 2 C A B B D B B D 2C 0 D A C 2 B A 45 45 45

Two objects of masses m and 4m are at rest at infinite separation They move towards each other under mutual gravitational attraction Then at a separation r which of the following is true A The total kinetic energy of the system is not zero B The force between them is not zero C The centre of mass of the system is at rest D All the above are true

One end of an ideal spring is fixed to a block of mass m and the other end is free The block is placed over a smooth horizontal floor Initially the spring is unstressed and the block is at rest Now the free end of spring is pulled to right with a constant horizontal velocity of magnitude v For this given spring b system match the statements given in column I with statements in column II 000000 77777 Column I A When the length of spring is maximum B When the length of spring is minimum C When the length of spring is equal to its natural length D When the net force on the block is zero Column II p the speed of block is v q the speed of block may be zero r the speed of block may be 2 v s the kinetic energy of block may be maximum

A tank contains a transparent liquid of refractive index The bottom of the tank is a plane mirror as shown A person at P looks at an object O and its image in the mirror The distance between the object and its image in the mirror as perceived by the person is 1 2 d 3 2 d P 0 2 4 2d H d H

C VC A N VAN VBN B R wwm R jX C jXca Rea R3 jX3 13a Find the magnitude of the delta current lab Ibic or Ica in A at the load Submit Answer Tries 0 3 13b Find the phase angle of the delta current lab in degree at the load Submit Answer Tries 0 3 13c Find the phase angle of the delta current Isc in degree at the load Ica Submit Answer Tries 0 3 13d Find the phase angle of the delta current Ica in degree at the load a lab jXab Rab Rbe jXbe Ibe www

48 A tank contains a transparent liquid of refractive indexu The bottom of the tank is a plane mirror as shown A person at P looks at an object O and its image in the mirror The distance between the object and its image in the mirror as perceived by the person is 1 2 d 3 2 d

When the system shown in the diagram is in equilibrium the rigth spring is stretched by 1 cm The coefficient of static friction between the blocks is 0 3 There is no friction between the bottom block and the supporting surface The force constants of the springs are 150N m and 450 N m refer figure The blocks have equal mass of 2kg each Find the maximum amplitude in cm of the oscillations of the system shown in the figure that does not allow the top block to slide on the bottom M 450 N m 0000 m 150 N m m 0000 AYAT

In a simple microscope f 6 cm the final image is produced at infinity Eye is placed at a distance of 1 cm behind the lens D 25 cm Magnification produced is 1 6 3 5 0 2 5 5 4 4

47 Critical angle of glass air interface is 0 and that water air interface is 02 The critical angle for glas edeconser 1 water interface would be 1 a 1 less than 0 3 greater than 3 2 between 0 and 0 4 lose than a

In free space a particle is projected from a point P on axis of a fixed rigid cone AOB at an angle a 37 with the axis see figure Distance of point P from the apex O is x 10 cm and the apex angle of the cone is 8 20 All the collisions of the ball with the cone are perfectly elastic Find the distance of closest approach of the ball from the apex in centimeters B P A O

3 An combination of a concave and convex lens has power 5 D If the magnitude of focal length of concave lens is 100 cm the power of convex lens is 1 1 D 3 4 D 2 2 D 4 6 D

A positive charge Q is fixed at a point A Another positively charged particle of mass m and charge q is projected from a point B with velocity u as shown in the figure The point B is the large distance from A and the distance d from the line AC The initial velocity is parallel to the line AC The point C is a very large distance from A The minimum distance in meters of q from Q during the motion is d 1 A Find the value of A Take Qq 47 omu d and d 2 1 meter B d

If an object moves towards a plane mirror with a speed v at an angle 0 to the perpendicular to the plane of the mirror find the relative velocity between the object and the image 0 1 V 2 2v 3 2x cosA 0 X

White light is incident on the interface of glass and air as shown in the figure If green light just undergoes total internal reflection then the emerging ray in air contains Air Glass White 1 Yellow orange red 2 Violet indigo blue 3 All colours Green Telegram o

1 An astronomical telescope for normal adjustment has magnitude of magnifying power 24 and tube length 150 cm The focal lengths of eye piece and objective lens are respectively 1 144 cm and 6 cm 3 6 cm and 144 cm 2 120 cm and 30 cm 4 30 cm and 120 cm

An electric dipole of dipole moment 10 6C m is released from rest in uniform electric field 10 V m at angle 0 60 Maximum rotational kinetic energy of the dipole is say K and maximum torque during the motion is then O K 5 0 x 10 5 J O T 5 0 x 10 N m 19 dan y O K 2 0 x 10 J O None of these

5 A ray of light passes through an equilateral glass prism in such a manner that the angle of incidence is equal to the angle of emergence and each of these angle is equal to 3 The angle of deviation is 1 45 3 39 of the angle of prism 2 70 4 30

52 An object and a screen are kept at a distance of 120 cm A lens is kept between them so that a real image is formed on the screen for two different positions of the lens Difference between the positions of the lens is 60 cm The focal length of the lens is 1 22 5 cm 3 20 cm 2 45 cm 4 20 5 cm

A circular ring carries a uniformly distributed positive charge The electric field E and potential V varies with distance r from the centre of the ring along its axis as O n n O n None of these

Two bodies of mass 4 kg and 6 kg are tied to the ends of a massless string The string passes over a pulley which is frictionless see figure The acceleration of the system in terms of acceleration due to gravity g is 1 g 2 to 4kg 2 g 5 6kg 3 g 10 4 None of these

Write the law of refraction of light beam in vector form using directing unit vectors e and e of the incident and refracted beams in medium of refractive indices 2 respectively and the unit vector of the outside normal to the interface of two mediums 441 14

36 Two particles of mass 1 kg each are moving in opposite direction with speed of 6 m s and 4 m s and undergoes collision with coefficient of restitution 1 Calculate loss in kinetic energy 2 75 4 3 75 2 4 300 8 3 4

An object with a mass 5 kg moves at a constant velocity of 8 m s A constant force then acts for 6 seconds on the object giving it a speed of 4 m s in opposite direction The acceleration produced is 1 1 5 m s 3 0 67 m s 2 2 m s 4 0 5 m s

When a diffraction pattern of a crystalline solid is recorded using an X ray beam of wavelength 0 26 nm the first order diffraction peak occurs at a scattering angle of 35 If the error in the measurements of angle and wavelength are 1 and 0 01 nm respectively then determine the error in measuring the interplanar spacing a 22 86 nm b 32 38 nm c 15 2 nm d 13 2 nm