Basic Physics Questions and Answers

5 8 In a given solenoid if the number of turns and the length of the solenoid are doubled keeping the area of cross section same then its inductance A Remains the same C Is doubled B Is halved D Becomes four times

A man is working as a labourer in a construction site He carries 10 bricks of 1kg each to the roof of a building 5m high by climbing a ladder 52 The amount of work done by the labourer is a 490 J b 940J c 500J d 380J

A cone of heighth and base of radius r is submerged in a fluid as shown in figure such that half of its height is outside the fluid The angle of contact between the fluid and cone is and surface tension for the fluid is T The net force experienced by cone due to surface tension is

Let P Q R be feet of perpendicular drawn from point A 1 1 on lines L y 2x 4 L2 y 2x 6 and L3 y 5 respectively B is point of intersection of L L Coordinate of mid point PR is O 0 7 O 1 2 1 2 5 1 5 0

what have been the answer if ins tead of can cannot has been a a sked and it might have been 2 i s it right You scored 0 of 4 Question 10 The minimum number of non coplanar vectors whose sum can be zero Options 3 4 2 5 Solution Answer 2 Fact Based

2 9 An ant is scampering on a paper with velocity 10 m s Now you begin to pull the paper with velocity 10 m s along x axis as shown in figure Coordinate system has origin fixed to ground as shown in figure The 3 initial position of ant is 0 0 Select the correct alternative s y 379 Motion of paper

Select correct option no 1 Error in a measurement cannot be greater than least count of the measuring instrument 2 Numerical value of the physical quantity is directly proportional to the unit of physical quantity 3 Numerical constant can be deduced by the method of dimensions ea 4 A number which is not a measured value has anificant figures

A swimmer can swim at a speed of 10 km h in still water A river of width 800 m is flowing at a speed of 6 km h Find the time taken to cross the river along the shortest path K 1 4 8 min 3 12 min EN 2 6 min 4 9 min

A number of bullets are fired in all possible direction with a horizontal velocity 10 m s from the height 20 m above ground The area on the ground covered by the bullets will be g 10 m s 1 200 m T 3 400 m TU 2 100 m 4 10 m

A block m is loaded into another block m on a spring of stiffness k as shown If m2 is suddenly removed the acceleration of m just after the removal of m2 is equal to O mm m m EE m g g Jammual m g m

ally incorrect option second option in this case will result in option in this case will result in 1 marks Selecting any incorrect option s second option in this case with A block is released from rest on an fixed incline plane from a height 6m above the ground as shown in figure where coefficient of friction between block and incline plane is 0 5 Choose the correct option s for motion of block from shown position to the bottom of incline I Change in potential energy is 300 J Work done by normal is 400 J Work done by friction is 200 J Final velocity of block when it just reaches to bottom of incline plane is 2 10 m s View In English dll Correct option selecting only all the three correct options will result in 4 marks Selecting only two of the three correct options e g marks Selecting only one of the three correct options either first or third or fourth option without selecting any incorrect option second without selection of any correct option s will result in 2 marks 6m 5kg fixed

Zero Marks 0 In all other cases A car is travelling with a speed of 90 m s due east An observer is present at 5 m south of the line of motion Find the angular velocity in rad sec of car relative to the observer when car is loe northeast of him

A small circular disk A travelling with speed u on a frictionless horizontal surface has a collision with an identical stationary disk B After collision the disks A and B move with speeds vandv 2 respectively along directions with an angle 60 between them Let the deviation experienced by the disk A due to the collision i e the angle between its initial and final velocity bee Which of these options is are cor TOP VIEW VE V 28 221 F cos 8 30 cos 0 30

13 What is a lever 14 Describe three orders of levers giving an example of each Draw neat diagrams showing the positions of fulcrum load and effort in each kind of lever phonical advantag

Zero Marks 0 In all other cases A rod is hinged at o and free to rotate about horizontal axis in vertical plane M are the mass and length of the rod A particle of mass m strikes the rod at P with n velocity vo op x when X L the impulse imparted by hinge on the rod is zero 3 What is the value of n 0 4 ir P

A train of length 225 m is moving towards north with a velocity of 10 m s A parrot flies at speed of 5 m s towards south parallel to the railway track The time taken by parrot to cross the train will be 10 s 15 s 20 s

A person travels along a straight road for the first th 1 time with speed v and for next th 3 4 a speed v The average speed of the person will be O V V 2 O V 4V 2 3 time with O V 3V

The particle A is mounted on a light rod pivoted at O and therefore is constrained to move in a circular arc of radius r If the velocity of A in terms of the downward velocity VB of the counterweight for 30 is XVB then find x 3 3 B y won r X

A charge of 50 nC is uniformly distributed over a hemispherical of radius 20 cm Electric field at the centre of the hemisphere will be nearly 50 nC 3 20 cm Adz G42 YgAga 5 faaka 21 u ma A 11 2 x 10 N C Your Answer B 2 8 10 N C C 5 6 x103 N C surface Correct Answer

If least count of an instrument is taken as absolute error then the relative error in the measurement of length 32 4 cm by a metre scale is 1 0 01 32 4 1 0 32 4 2 4 0 1 32 4 0 001 32 4 evip number cm me de rakkha hai lekin usko measure metre scale se kiya jaa raha hai mujhe is question me

5 47 In figure 5 302 the switch is in the position 1 for a long time then switch is shifted to position 2 at t 0 At this instant the value of i and i are A 0 R C E E 2R 2R E R www eeeeee 2 Figure 5 302 R ellele 2 E E R R D None of these

LO Ough 5 48 When an AC source of E across a circuit the phase difference between the EMF e and the current i in the circuit is observed to be 4 as shown in the figure 5 303 If the circuit consists possibly only of RC or LC in series find the relationship between the two elements i or e i A R 1k C 10 F C R 1kQ C 10H Figure 5 303 B R 1kQ C 1 F D R 1kQ L 1H

A system of two blocks are connected by the heavy rod of mass 10 kg and length is 5 m Forces of 100 N and 40 N are applied on block of 8 kg and 2 kg respectively All surfaces are smooth Find the acceleration of 2 kg block O 3 m s O 6 m s 2m 40N 2kg W 8kg 100N

A liquid of density p is filled in a U tube is accelerated with an acceleration a so that the height of liquid in its two vertical arm are h and h as shown in the figure It is the length of the horizontal arm of the tube the acceleration a is 1 2 h g h h 2l g h h 28 g hi h l 3 4 g hi h L right left l left right h

Two bodies one held 100 cm directly above the other are released simultaneously from the large height and both fall freely under the gravity The separation between the bodies just after 2 s will be O 50 cm O 100 cm O 80 cm O 120 cm

A cricketer hits a ball with a velocity 25 m s at 60 above the horizontal how far above the ground it passes over a fielder 50 m from the bat cassume the ball is struck very close to the ground 1 8 2 m 3 11 6 m 2 9 0 m 4 12 7 m

5 54 Find the current passing through battery immediately after the key K is closed It is given that initially all the capacitors are uncharged Take R 692 and C 4 F VASTA 1A C 3A K TE 5V R www R ww R ww L oooooo R www R www C 16 C C Figure 5 307 B 5A D 2A

cance of y 5kHz nnected m 5 43 Acircular ring of diameter 20cm has a resistance 0 0102 How much charge will flow through the ring if it is rotated from position perpendicular to the uniform magnetic field of B 2T to a position parallel to field A 4C B 6 28C C 3 14C D 25 12C

Consider motion of a planet in elliptical path around the sun Choose corre alternative B A A Time taken by planet to move from point A to B is equal to time taken by planet to move from point D to A B Time taken by planet to move from point B to C is equal to time taken by planet to move from point D to A C Time taken by planet to move from point C to D is greater than time taken to move from point D to A D Angular momentum of planet about the centre of sun remains conserved throughout the motion

5 56 A rectangular loop of sides a and b is placed in x y plane A uniform but time varying magnetic field of strength B 20t 10t j 50k is present in the region The magnitude of induced EMF in the loop at time t is A 20 20t C 20t B 20 D Zero

SECTION 1 This section contains 20 Multiple Choice Questions Each question has 4 choices A B C and D out of which ONLY ONE CHOICE is correct 1 Two forces each numerically equal to 5 N are acting as shown in the Figure Then the resultant is SN 60

A mass M is suspended from a light spring An additional mass m added displaces the spring further by a distance x Now the combined mass will oscillate by the spring with period 1 T 2T 1 T AT 3 T 2 el mg x M m mg 2 x M m 4 T 2 M m x mg M m mgx Am glm

Mass M placed on a fixed horizontal rigid wire is attached to a massless spring whose other end is fixed to a wall The spring and the attached mass M can move on the fixed horizontal rigid wire Another mass m is joined by a wire to mass M and freely hanging like a pendulum in the vertical plane as shown in the FIG Total number of generalized coordinates of the system is 04 O 1 M m

Figure shown is a graph at a certain time t of the displacement function S x t of three sound waves 1 2 and 3 as marked on the curves that travel along x axis through air If P P and P3 represent their pressure amplitudes respectively then correct relation between them is 3 1 a P P P3 c P P P 2 b P3 P P d P P P

Your little brother is playing with a triangular toy cart as shown To make some fun you drop a small ball vertically on to the cart The ball hits the cart elastically with a velocity 4 m s If the cart was moving with a speed 4 m s as shown calculate the velocity of the ball after the collision Assume the mass of the cart is very large than the ball 415 4 3 94m s 4m s 45

In phenomenon of resonance of series LCR circuit the total source voltage appears across Resistor Inductor 19 29 min sec Capacitor

A transverse harmonic wave represented by y A cos kx wt travels along a string towards a boundary at x 0 with a 2nd string The speed of wave in 2nd string is half of speed of wave in string 1 Then the equation of reflected wave is o y y 3 2A 3 y 3 cos wt kx cos kx wt cos kx wt y sin kx wt

Consider a hypothetical hydrogen like atom The wavelength of spectral line from pth orbit to ground state is given by considered hypothetical atom hC 1240 eV nm The ionization potential of considered hypothetical atom is 3 54 V approximately The ionization potential of considered hypothetical atom is 0 354 V approximately The wavelength of least energetic photon in the spectral line series is 466 67 nm approximately The wavelength of maximum energetic photon in the spectral line series is 350 00 nm approximately 3500p p 1 in Choose the correct option s fe

A horizontal spring block system of spring k and block mass M respectively executes simple harmonic motion with amplitude A When the block reaches the extreme end an object of mass m is gently dropped on it and the two move together The new amplitude of oscillation will be A 1 1 A 3 A M M m E m M 2 A 4 A m M E

4 Suppose a gas sample contains 3 x 104 molecules Each 1 3rd of the molecules have speed 2 x 103 cm s 3 x 103 cm s and 4 x 103 cm s The rms speed in cm s of gas sample will be NCERT Pg 148 1 2 3 29 x 106 3 11x106 3 3x106 V

A point mass m is moving in a horizontal circle of radius L with the help a wire Y A L as shown If the speed of mass is vo then elongation in th wire will be A cross sectional area of wire Y Young s modulus A 2mv2 YA mv C 2YA Y A L B D mv YA Pm 3mv YA

planet of mass M and radius R as shown in the figure A particle is projected from the surface of the planet at an angle 8 from radial direction and with velocity equal to the orbital velocity of circular orbit at that point then choose the CORRECT statement s M R P Vo

A particle is projected in upward direction from the surface of the earth It is found that potential energy is negative of four times the kinet Vescape Findout value of n energy If the projection speed is n

A block of weight 40 N placed on a rough horizontal surface is being pushed with a constant force of 50 N If the maximum static friction between block and surface is 60 N then Only One Correct Answer A B C D The frictional force acting on the block is 60 N The block will not move The block will move with increasing speed The block will move with constant speed

Consider the region D in the first quadrant of R2 bounded by the curves y x 9y x y and 16x y3 as pictured below 3 2 1 Y 16r y3 D 2 9y 2 r y 3 I 4 a Find a transformation u v T x y such that the image T D of D under T is a rectangle in the uv plane Justify your answer x y b Find the Jacobian Express your answer in terms of u and v a u v c Use the change of variables theorem to compute ff1dA d What goomotr quentity doon

Consider a satellite S which is just above the Brazil and rotating on equatorial plane of earth The sense of rotation of earth and satellite are similar means both are rotating from west to east The time period of satellite is 6 hours At t 0 satellite is just above the Brazil Now choose the correct option s S Brazil To Earth The time after which the satellite will be above the Brazil again is 8 hours The above satellite may be a geostationary satellite The height of geostationary satellite above the sea level is 35 800 km approximately If the distance from the centre of earth to the satellite S becomes 4ro then the time after which the satellite will be above the Brazil again is 24 hours

Question 11 An electron of mass me and a proton of mass mp 1836 m are moving with the same speed The ratio of their de Broglie wavelength Aelectron Aproton will be a 918 b 1836 c 1 1836 d 1

Question No 92 Max Mark s 04 Multiple Choice Select 1 out of 4 options for the question below If n number of identical resistors are connected in parallel combination then the effective resistance of the combination is Options OOO nR CR

Two identical AC BC inclined at 60 X 30 to the horizontal plane at C A load of 100N rething on inclined plane BC at lie by rope passing a block of neeight of block w nesting on AC If the ceff of friction bfw load plane Be is 0 28 x b w the block plane At is 0 20 Find the least X greatest value of N for equillibrium of cys W 160 11 0 20 100 4 U 0 28 30

Two gases have the same initial pressure volume and temperature They expand to the same final volume one adiabatically and the other isothermally The final temperature is greater for the isothermal process The final pressure is greater for the isothermal process The work done by the gas is greater for the isothermal process All the above options are incorrect