Physics Questions

Example 8 5 The planet Mars has two moons phobos and delmos i phobos has a period 7 hours 39 minutes and an orbital radius of 9 4 x10 km Calculate the mass of mars ii Assume that earth and mars move in circular orbits around the sun with the martian orbit being 1 52 times the orbital radius of the earth What is the length of the martian year in days

The coefficients of apparent expansion of a liquid when determined using two different vessels A and B are y and Y2 respectively If the coefficient of linear expansion of the vessel A is a the coefficient of linear expansion of the vessel B is A B C D ay1Y2 Yi 12 11 Y2 2a Y1 Y2 a 3 Y1 2 3 a Correct Answer

08 The elevator shown in figure is descending with an acceleration of 2 ms 2 The mass of the block A 0 5 kg The force exerted by the block A on the block B is A 2 N B 4 N A B 2 ms 2 C 6 N D 8 N

A particle of mass M moves in a circular orbit in such a way that the potential energy is U ar where a is a constant an r is the distance of particle from the origin Assuming the Bohr s quantization rule to be valid find the radius of nth allowed orbit O O r n h 8 aM nh 8 aM 1 4 nh 8 aM 2 1 2 n h 14

1 If x and y be the distances of the object and 31 image formed by a concave mirror from its focus and f be the focal length then 1 xf y 2 xy f 3 x y f 4 x y f

A steel rod of length 1m is heated from 25 C to 75 C keeping its length constant The logitudinal strain developed in the rod is Given coefficient of linear expansion of steel 12 10 6 C A 6 x 10 3 C 6x 10 5 6 10 4 zero My Answer Correct Answer

A convergent lens of 6 diopters is combin with a diverging lens of 2 diopters Find power of combination 1 4 diopter 2 6 diopter 3 8 diopter 4 10 diopter

Optical fibre consists of core and claddin whose refractive index are related as 1 core clading 2 core clading 3 core clading 4 No relation between them

A truck starts from rest and accelerates uniformly with 2 ms 2 At t 10 s a stone is dropped by a person standing on the top of the truck 6 m high from ground What are the a velocity and b acceleration of the stone at 1 11 s Neglect air resistance

A force produces an acceleration of 4 ms 2 in a body of mass m kg and the same force produces an acceleration of 6 ms 2 in another body of mass m If the same force is applied to m m then the acceleration will be A 10 ms 2 B 2 ms C 2 4 ms D 5 4 ms 2

The work function of a metallic surface is 5 01 eV The photoelectrons are emitted when light of wavelength 2000 falls on it The potential difference applied to stop the fastest photoelectron is h 4 14 x 10 15 eV O 1 2 V O 2 24 V O 3 6 V O 4 8 V

3 A metal plate of area 10 cm rests on a layer a oil 6 mm thick A tangential force 102 N is applied on it to move it with a constant velocity of 6 cms The coefficient of viscosity of the liquid is 1 0 1 poise 2 0 5 poise 3 0 7 poise 4 0 9 poise

In secondary rainbow there are 1 1 total internal reflection 2 2 total internal reflection 3 No internal reflection 4 Depends on the size of water droplet WOW 13 Edlech s 1 2 a 3 4 3

The P V diagram 2 g of helium gas for a certain process A B is shown in the figure What is the heat given to the gas during the process A B P 2P Po A 0 C Vo 4P V B 5P V 6P V 2V V Correct Answer

A beam of light of wavelength 600 nm from a distance source falls on a single slit 1 mm wide and a resulting diffraction pattern is observed on a screen 2 m away The distance between the first dark fringes on either side of central bright fringe is A 1 2cm B 1 2mm C 2 4cm

2 amu mass of a small atom A moves x direction from atom B which is remain stationary energy of between two particles U x 40 x at time 0 position of atom A x t 1 5 velocity of atom A v t 2 3 x direction away from B find acceleration velocity and position at t 0

Two identical flutes produce fundamental notes of frequency 300 Hz at 27 C If the temperature of air in one flute is increased to 31 C the number of beats heard per second will be A B 1 2 3 C Correct Answer

direction of ray of light incident on a concave mirror is shown by PQ while direction in which the would travel after reflection is shown by four rays marked 1 2 3 and 4 which of the four rays correctly shown the direction of reflected ray P 24 f f r fa st a

20 Find the equivalent resistance between A and B if each resistor has a resistance R A m ww m R

14 15 The following graph shows two isotherms for a fixed mass of an ideal gas The ratio of r m s speed of the molecules at temperatures T and T is P 10 Pa 3 2 1 0 2 V m 3 T ALLI 1 2 2 2 2 3 2 4 4 Six moles of an ideal gas perfomrs a cycle shown 15

If an object is placed in front of a conca mirror and the lower half of the mirror covered with opaque material then w happens 1 lower half of the object will be seen as im 2 upper half of the object will be seen as im 3 No change in the image will taken pl 4 image will be completely formed with less inte

TON S LAWS Two blocks of masses 2 kg and 1 kg are in contact with each other on a frictionless table When a horizontal force of 3 0 N is applied to the block of mass 2 kg the value of the force of contact between the two blocks is A 4 N B 3 N C 2 N D 1 N

9 Two drops of equal radius coalesce to form bigger drop What is ratio of surface energy c bigger drop to a smaller one 1 21 2 1 2 1 1 3 22 3 1

An ac millivoltmeter has a range of 0 1000 mV and its accuracy is 0 5 of fsd full scale deflection If the input voltage of the instrument is 400 mV the output of the instrument would be a 402 mV c between 398 and 402 mV b 398 mV d between 395 and 405 mV

A short pulse of white light is incident from air to a glass slab at normal incidence After travelling through the slab the first colour to emerge is 1 Blue 2 Green 3 Violet 4 Red

A linear aperture whose width is 0 02 cm is placed immediately in front of a lens of focal length 60 cm The aperture is illuminated normally by a parallel beam of wavelength 5 x 105 cm The distance of the first dark band of the diffraction pattern from the centre of the screen is a 0 10 cm b 0 25 cm c 0 20 cm d 0 15 cm

36 Energy released in nuclear fusion and fission processes is due to A conversion of the mass difference into energy B chemical reaction C kinetic energy of parent nuclei D above

V i m V i m2 m2 2 00kg Two masses collide in one dimension m1 6 00kg v1i 10 0 m s v2i 4 00 m s After the collision mass m1 has velocity of v1f 7 00 m s If the collision lasted for a time 0 025 seconds what is the average collision force acting on mass m2 during the collisi Answer in newtons

A body is projected vertically up at t 0 with a velocity of 98 m s Another body is projected from the same point with same velocity after time 4 seconds Both bodies will meet after A 6 s C 10 s B 8 s D 12 s

B In telescope which mirror is used as objective instead of convex lens 1 Parabolic concav mirror 2 Plane mirror 3 Convex mirror 4 Mirror can t be used

1 Twelve wires of resistance R each are joined to form a cubical frame Calculate the equivalent resistance between i Two diagonally opposite vertices ii Two adjacent vertices

Give the magnitude and direction of the net force acting on a a drop of rain falling down with a constant speed b a cork of mass 10 g floating on water c a kite skilfully held stationary in the sky d a car moving with a constant velocity of 30 km h on a rough road e a high speed electron in space far from all gravitational objects and free of electric and magnetic

Unpolished half is unpolished Flashlight beam O In a dark room this coin is placed face up on the floor and illuminated with a thin beamed flashlight as shown in figure A and B look at the coin from the position as indicated in figure Beye A Polished coin A eye Floor According to A which half of the coin if either is brighter 1 The polished half 2 The unpolished half 3 Both halves look equally bright

Level 9 Which of the following relations associated with Newton s second law ramains valid for all velocities dv dt C F 4 mv A F ma B F m D All of them

light and d olet light are incident at the same angle on the inclined surface of a prism from air me dium and produce angles of refraction r and v respectively which of the following is c orrect A r v B r v C r 1 v D r v

TON S LAWS Two masses 2 kg and 3 kg are attached to the ends of the string passed over a pulley fixed at the top and accelertion in the string in terms of g are A 78 8 9 8 8 B 21g g 8 8 C 218 g 8 5 g 5 5 D 12 8

A battery of unknown emf connected to a potentiometer has balancing length 560 cm If a resistor resistance 1002 is connected in parallel with the cell the balancing length change by 60 cm If th internal resistance of the cell is 10 O the value of n is

A block of mass m is connected with a spring of spring constant k and placed on a smooth horizontal surface as shown in the figure The block is then moved to compress the spring by 10 2 cm and then released The collision between block and the wall is elastic The time period of oscillation is k mmmmmmmm 3 1 3T 2 3 T H T 10 cm 19

A passenger in an aeroplane shall 1 Never see a rainbow 2 may see a primary and a secondary rainbow as concentric circles 3 may see a primary and a secondary rainbow as concentric arcs 4 shall never see a secondary rainbow

A person can see his inverted image in a concave mirror when he is 1 between focus and center of curvature C 2 beyond C 3 between focus pole 4 at focus

A liquid mixture of volume V has two liquids as its ingredients with densities and B If density of the mixture is a then mass of the first liquid in mixture is 1 3 av o 1 B a a aV B o 2 4 av a B a B av 1 00 Plex

View In English A solenoid has an inductance of 50 mH and a resistance of 0 025 0 If it is connected to a battery how long will it take for the current to reach one half of its final equilibrium value 1 2 3 4 Correct Answer 1 1 39 s 12 s 6 32 s 0 23 s D

Graph between terminal voltage V V and current flowing through the same cell is shown Current direction from 1 to 2 is taken as positive B Portion AB indicates charging of cell 2 1 Portion BC indicate discharging of cell Neither 1 nor 2 Both 1 2

A parallel plate capacitor with plates of area 25cm is separated by a distance of 0 05mm The dielectric constant of t he medium between the plates is 8 Th e capacitor is connected to a battery of potential difference 50V Calculate a t he charge collected by the capacitor an d b the electric field between the plate

A particle moves along x axis with speed 6 m s for the first half distance of a journey and the second half distance with a speed 3 m s The average speed in the total journey is A 5 m s C 4 m s B 4 5 m s D 2 m s

becomes 4 times hen a tiny circular obstacle is placed in the path of light from distante source What is observed at the centre of the shadow of the obstacle 1 Dark spot 2 Bright spot 3 Dark bright fringe 4 None

24 A capillary tube is dipped in water and it is 20 cm outside water The water rises upto 8 cm If the entire arrangement is put in freely falling elevator the length of water column in the capillary tube will be 1 20 cm 2 4 cm 4 8 cm 3 10 cm

Two radioactive substances A and B have decay constants 4 and respectively At t 0 they have the same number of nuclei The ratio of number of nuclei of A to those of B will be after a time interval of 1 2 2 3 a

John is pulling a box forward with a force of 100N and the force forms an angle of 30 elevated from the horizontal The mass of the box is 20kg and the box is at rest at the beginning If the coefficient of kinetic friction is 0 2 and the coefficient of static friction is 0 3 answer the following questions Show your steps g 10m s 1 Determine if the box will start moving Support your argument with relevant calculation 3A 2 the frictional force 2A 3 Determine the acceleration of the mass if it ever starts moving 3A

35 Water is filled in a tank upto 3 m height The base of the tank is at height 1 m above the ground What should be the height of a hole made in it so that water can be sprayed upto maximum horizontal distance on ground 1 3 m from ground 2 1 5 m from ground 3 1 5 m from base of tank 4 2 m from ground 3 m 1m 2 42