Basic Physics Questions and Answers

Four point charges Q q 2q and 2Q are placed one at each corner of the square The relation between Q and q for which the potential at the center of the square is zero is 1 Point Q q Q q Q 1 q Q 1 q

Find the electric potential difference VB VA due to a point charge q 2 74 nC that is 0 260 m from location A and 0 460 m from location E V A charge q2 moving from B to A gains in kinetic energy What is the sign of this charge Onegative positive

Two coherent sources S and S2 are kept on the edges of a step as shown in the figure An infinitely long screen is placed the right side of sources and lies along y z plane Calculate total no of maximas observed on the screen PS 1 82 and S2 62 Where is wavelength of light used There is no reflection from steps 8A O 18 O 16 C 14 12 64 Screen

The figure shows a plane wave front at a time t and at a time t In the time interval t t the wave front must have passed through A a prism B a prism and a convex lens C a convex lens D a plane mirror and a concave lens at t

The figure shows a plane wavefront at a time t and at a time t 1 In the time interval t t the wavefront must have passed through at t at t Ta O a prism O a prism and a convex lens a convex lens O a plane mirror and a concave lens

Question When the current I is flowing through a conductor the drift velocity is v If 21 current flows through the same metal but having double the area of cross section then the drift velocity will be 1 Point V 4 v 2 OV 4

Q No 11 A material is said to be allotropic if it has fixed structure at all temperatures atoms distributed in random pattern different crystal structures at different temperatures any one of the above ABCD A C D

2 Thermoplastic materials are those materials which are formed into shape under heat and pressure and results in a permanently hard product Q No A B do not become hard with the application of heat and pressure and no chemical change occurs C are flexible and can withstand considerable wear under conditions suitable D are used as a friction lining for clutches and brakes

0 In case if no response is typed selected In the arrangement shown in figure image of light source O is to be obtained at the bottom of beaker containing water upto height 20 cm Find H f 30 cm 36 cm 1m 45 20 cm

Q No 7 The hardness is the property of a material due to which it ABCD A B C D can be drawn into wires breaks with little permanent distortion can cut another metal can be rolled or hammered into thin sheets

Q No 14 An alloy steel which is work hardenable and which is used to make the blades of bulldozers bucket wheel excavators and other earth moving equipment contain iron carbon and ABUD A B C D chromium silicon manganese magnesium

Q No 1 Specify the sequence correctly ABCD A B C D Grain growth recrystallisation stress relief Stress relief grain growth recrystallisation Stress relief recrystallisation grain growth Grain growth stress relief recrystallisation Knowledge Sections

The ratio of the energy released by 4 kg of hydrogen at sun by fusion process to 23 5 kg of 235U in the nuclear reactor by fission process is Assume energy released per fusion is 26 MeV and that per fission is 200 MeV A 5 13 B 1 26 02T C 13 10 000 D 10 13 E 26 1

An uncharged capacitor C 100 F is connected in series with 50 2 and with AC source as shown in the figure If switch S is closed at t 0 the maximum value of VA V is K volt Calculate K C 100 F wwww 10002 B 16 sin 100t www R www 10002 S

H INSTITUTE RAM TAFOR 33 A block of mass 10 kg is moving on a rough surface as shown in figure The friction force acting on block is 1 20 N 3 40 N 06 v 4m s 10kg F 20N 2 60 N 4 80 N

A point object O is moving with velocity 20 2 m s and a plane mirror is also moving with a velocity 10 m s as shown in the figure Then 10 m s 20 2 Z 45 the separation between the image and the mirror increases the separation between the image and the mirror decreases the velocity of image with respect to ground is 20 m s and parallel to the mirror the velocity of image with respect to ground is 40 m s and parallel to the mirror

O Lymph Carries digested and absorbed amino acids Normal systolic 120 mm Hg in pressure human beings O Veins Have valves Pulmonary arteries Carry carbon dioxide rich blogod

Q No 9 Smelting is the process of A removing the impurities like clay sand etc from the iron ore by washing with water B expelling moisture carbon dioxide sulphur and arsenic from the iron ore by heating in shallow kilns C reducing the ore with carbon in the presence of a flux D all of the above

5 a Draw the ci b A DC long shunt compound generator delivers a load current of 200A at 450V The resistance of the armature series field and shunt field are 0 03 2 0 015 2 and 150 2 Calculate the emf induced in the armature Allow a brush drop of 1V brush a Derive the condition for obtaining maximum power from a source to resistive load 2x6 12 Marks cal transformer Draw phasor diagram at different loads for an ideal transformer

The system is pushed by a force as shown in figure All surfaces are smooth except between B and C Friction coefficient between B and C is u Minimum value of F to prevent block B from downward slipping is c 5 mg 3 a 2 mg 5 b mg 2 F A B m 2m d 2 m umg C 2m

Q No 12 Closed packed hexagonal space lattice is found in A bismuth B gamma iron aluminium copper lead silver and nickel C D zinc magnesium cobalt cadmium antimony and alpha iron tungsten chromium and molybdenum none of the above

The limiting friction between two bodies in contact is independent of 1 Nature of the surface in contact 2 The area of surfaces in contact 3 Normal reaction between the surfaces 4 The materials of the bodies

Revisit in a certain transistor collector current is 0 98 mA and base current is 0 02 mA Determine the values of emitter current and current amplification factor 2 marks C04 Choose the best option 1 mA 0 49 O 2 mA 0 49 O 1 mA 0 98 O 2 mA 0 98

8 a b Design an op amp circuit with inputs v1 and v2 such that v 5v1 3v2 6 bu For the op amp circuit is given below Figure 7 Calculate the output voltage Vo 5 4 kn wwww 44 10kn ww Vo

c may move toward the mirror if the mirror is concave d must move toward the mirror if the mirror is convex 8 A real point source is 5 cm away from a plane mirror whose reflecting ability is 50 while the eye of an observer pupil diameter 5 mm is 10 cm away from the mirror Assume that both source and eye are on the same line perpendicular to the surface and refracted rays have no effect on intensity Then a the area of the mirror used in observing the image of source is 257 36 mm b the area of the mirror used in observing the image of source is 25 mm c the ratio of the intensities of light as received by the observer in the presence to that in the absence of mirror is 10 9 d the ratio of the intensities of light as received in the

Q5 Length of a wire at room temperature s 4 55 m when the temperature increases upto 100 C then its length becomes 4 57 m The coefficient of linear expansion a of the given wire is a 5 021 x 10 5 K 1 b 6 021 x 10 5 K 1 c 7 021 x 10 5 K 1 d 8 021 x 10 K 1

converge Ans 48 cm behind the lens 30 A double convex lens has 10 cm and 15 cm as its two radii of curvature The image of an object placed 30 cm from the lens is formed at 20 cm from the lens on the other side Find the focal length and the refractive index of the material of the lens What will be the focal length of the lens if it is immersed in water of refractive index 1 33 Ans 12 cm 1 5 47 cm 31 An illuminated object and a screen are 90 cm apart 1 Col Iaurth of a lons required to MC 4

A particle having mass equal to mass of the earth is projected by an external agency so that there is no recoil in earth when particle is projected In this case escape velocity of the particle will be kgR g is acceleration due to gravity on the surface of the earth and R radius and earth Then find the value of k assuming gravitational force only acts between two masses and no other mass is present

If the size of particles is larger than wavelen gth of light then it will scatter all 7 colours VIBGYOR equally and together their combin ed effect will be white Now if the size of p articles is less than wavelength of light then it will scatter light of shorter wavelength it scatters light of maximum wavelength but ery very less scattering happens For eg Oxygen and nitrogen molecules in air scatte r bluish green side of spectrum and hence s ky appears blue since our atmosphere consi sts of 78 percent of nitrogen and 21 Percent of oxygen Mam can I write this answer in my exam i s it correct or wrong mam if there is anyth ing which is wrong so mam please seriousl y tell me mam I have written this myself o nly Even a silly mistake you will notice please let me know mam

Q13 A beaker is completely filled with water at 4 C It will overflow if a Heated above 4 C b Cooled below 4 C c Both heated and cooled above and below 4 C respectively

Q11 Two spheres A and B are made of the same material and have the same radius Sphere A is hollow and sphere B is solid Both the spheres are heated to the same temperature Which of the following is correct a A expands more than B b A expands less than B c Both the spheres expand equally d Data is insufficient

The vapour pressure of a solution of a non volatile solute B in a solvent A is 95 of the vapour pressure of the solvent at the same temperature If the molecular weight of the solvent is 0 3 times the molecular weight of the solute what is the ratio of weight of solvent to solute

Q3 The freezing point on a thermometer is marked as 20 and the boiling point as 130 A temperature of human body 34 C on this thermometer will be read as a 31 b 51 c 20 Yd None of theso

Q12 A cylindrical metal rod of length L is shaped into a ring with a small gap as shown On heating the system td a x decreases r and d increases b x and r increase d decreases c x r and d all increase d Data insufficient to arrive at a conclusion

Five point charges q each are placed at the five vertices of a regular hexagon The distance of the center of the hexagon from any of the vertices is a The electric field at the center of the hexagon is b c d zero 9 4 q 8a q 16

A block of mass m containing a net negative charge q is placed on a frictionless horizontal table and is connected to a wall through an unstretched spring of spring constant k If the horizontal electric field E parallel to the spring is switched on then the maximum compression of the spring is E J ight of Dreams a qE k b 2qE k ooooo m 9 c qE k d zero

Q8 A brass wire 1 8 m long at 27 C is held taut with negligible tension between two rigid supports Diameter of the wire is 2 mm its coefficient of linear expansion Brass 2 10 5 C 1 and its Young s modulus YBrass 9 x 10 0 Nm 2 If the wire is cooled to a temperature 39 C tension developed in the wire is a a 2 7 10 N b 3 7 10 N c 4 7 x 102 N d 5 7 x 10 N

Two light springs S and S of spring constants K 100N m and K 200N m are connected in series A man is keeping the springs stretched by applying a force of 50N Column I A work done by S on S B work done by S on S C work done by S on S and man D work done by man on S S C Chino 2 K K2 Column II P 18 75 J Q 6 25 J R 12 5 J S 12 5 J

At t 0 switch is closed to position 1 Capacitor is initially uncharged At T t switch is shifted to position 2 Then current as a function of time t is 200 the angular frequency A CVow cos t C CVow 1 sin cot 1 LC C L 0000000 2 voooooo L B CVow 1 cosct D CV sin cot

Q In a Gravity free space ice melts the height by which Centre of ind Mass Shifts m 96 is a cube of ength mass of cuba m GTray is M M

Vo ng y axis in a region of uniform magnetic field Bo which is outward and perpendicular to the plane of the paper as shown in the figure y O O O 10 Olo O The particle is continuously subjected to a frictional force which varies with velocity as F av where a is a constant Consequently the particle moves on a spiral path till it comes to rest at point P Find the x co ordinate of point P Take a 10 kg s q 10C Bo 1T va 1 m s m 20 g Rate this question

If two rods of length L and 2L having coefficients of linear expansion a and 2a respectively are connected so that total length becomes 3L the average coefficient of linear expansion of the composite rod equals A 3 2 a B 5 2 a C 5 3 a

There are two identical small holes of area of cross section A on the opposite sides of a tank containing a liquid of density p The difference in height between the holes is h Tank is resting on a smooth horizontal surface horizontal force which has to be applied on the tank to keep it in equilibrium is h

A 741 op amp has an open loop voltage gain of 2 105 input resistance of 2 M and output resistance of 50 The op amp is used in the below given circuit Figure 6 Find the closed loop gain Vo Vs Determine current I when Vs 2V lokn Mmm 1 TV Vd www mumsokn Ri 2 M www Avd

A charged particle of mass m 5 gm and charge q 12 C enters along AB at point A in a uniform magnetic field of magnitude B 100 Tesla existing in a rectangular region of size 8m x 6m and into the plane of paper as shown in figure The particle leaves the region at C The speed of the charge particle in m s as it leaves the region is X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XXXXXXXXX X X X X X 8 m X X X X X XXXXXX A B 6 m

In the turbine of a gas turbine unit the gases flow through the turbine at 17 kg s and the power developed by the turbine is 14 000 kW The specific enthalpies of the gases at inlet and outlet are 1200 kJ kg and 360 kJ kg respectively and the velocities of the gases at inlet and outlet are 60 m s and 150 m s respectively Calculate the rate at which heat is rejected from the turbine Find also the area of the inlet pipe given that the specific volume of the gases at inlet is 0 5 m kg Fia 1 24 From

The horizontal acceleration that should be given to a smooth inclined plane of angle sin 1 to keep an object stationary on the plane elative to the inclined plane is 1 g P 1 2 g P 1 3 1 g A borse pulls the cart Which of the following

37 53 C 1 Zero 2 35 N 3 49 N 4 70 N Two bodies A and B each of mass M are fixed 8 together by a massless spring A force F acts on the mass B as shown in fig At the instant shown the mass A has acceleration a What is the acceleration of mass B B 1 F M a 3 a 2 a 4 F M A person of mass 60 kg is inside a lift of mass 940 kg and presses the button on control panel 9

1 12 8 N 2 16 N 3 18 2 N 4 Zero In the give figure find out force exerted b pulley on clamp 5 kg 37 15 kg 53 C 1 Zero 2 35 N 3 49 N 4 70 Two bodies A and B each of mass M are fixe

A horse pulls the cart Which of the follow orces makes the horse move 1 Force exerted by the horse on the ca 2 Force exerted by the ground on the c 3 Force exerted by the ground on the he 4 Force exerted by the horse on the gro