Basic Physics Questions and Answers

5 61 Figure 5 312 shows an isosceles triangular wire frame with apex angle equal to 1 2 The frame starts entering into the region of uniform magnetic field B with constant velocity v at t 0 The longest side of the frame is perpendicular to the direction of velocity If i is the instantaneous current through the frame then choose the alternative showing the correct variation of i with time t 0 90 IX I 1 I 1 IX 1 B VX X X X X X X X

Two amplifiers are connected one after the other in series cascaded The first amplifier has a voltage gain of 20 dB and the second has a voltage gain of 20 dB The overall gain of the amplifier will be O 40 dB O 400 dB O 1 dB O 10 dB

The output of the given circuit in figure shown R ww VC A Will be zero for all time O Is Half wave rectified with Positive cycle in output O Is Half wave rectified with negative cycle in output Is full wave rectified

A horizontal plane support a stationary vertical cylinder of radius 1 m and a small disc A attached to the cylinder by a horizontal thread AB of length 4 m An initial velocity 2 m sec is imported to the disc as shown How long will it move along plane until it strikes agains the cylinder The friction is assumed to be absent O2 seconds O4 seconds O 8 seconds 06 seconds 1m BH 4m

The separation L between the objective f 0 5 cm and the eyepiece f 5 cm of a compound microscope is 7 cm A small object is placed infront of objective lens such that the eye is least strained to see the final image Find the angular magnification produced by the compound microscope 15 10 12 5

i and are unit vectors along x and y axis respectively What are the magnitude of components of a vector 51 along the direction of i j and i j A B C D 5 and 1 2 2 and 3 2 2 and 3 13 and 13

ne h d 5 26 A 120V AC source is connected across a pure inductor of inductance 0 70H If the frequency of the source is 60Hz the current passing through the inductor is B 0 355A D 3 55A A 4 55A gr 0 4 0 455A

Two radioactive substances A and B have decay constants 4X and A 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 27 03 20 O 1

5 53 Two coils have mutual inductance of 0 005H The current changes in the first coil according to equation I I sin cor where I 10A and o 100 rad s The maximum value of EMF induced in the second coil is A 2 V C TV B 5nV D 4TV

In the reaction H H He n If the binding energies of H H and He respectively E E and E then the energy released in this reaction is O E E E O E E E O E E E O E3 E E

How long can an electric lamp of 500 W be kept glowing by fusion of 2 kg of deuterium Take the fusion reaction as H H He n 3 27 MeV O 3 15 x 1011 s O 3 15 x 1014 s O 3 15 107 s 0315x108 s

The set which represents the isotopes isobars and isotones respectively is 198 O H 79Au 80Hg s 2He 1H 197 T 3 O 1H 1H 2He 1H 791 197 3 197 O 2He 1H 1H 1H 79 A 80Hg 198 198 80 Hg 3 O 2He 1H 78Au 0 H H 198 79 80 Hg

v is the frequency of series limit of Lyman series 2 is the frequency of the first line of Lyman series and v is the frequency of the series limit of Balmer series then V V V3 O V V V3 1 V V V3 1 1 V V3 01 V

3 Y X 4 2 A car start moving from rest on a horizontal ground such that the position vector of a car with respect to it s starting point is given as r bti ct i where a and b are positive constants The equation of trajectory of car y f x is 1 y x 2 y 4 y 11 5 x 0 r The velo in a d 3 2 2 7 ve

Hydrogen atom from excited state comes to the ground state by emitti a photon of wavelength If R is the Rydberg constant the principal quantum number n of the excited state is O O R VAR 1 7 VR 1 R

If a B and y are angles which is made by a vector with x axis y axis and z axis respectively then A B C D cos a cos B cos y 1 sin a sin sin y 2 cos2a cos2p cos2y 1 All of the above

Two identical small balls A and B each of mass m connected by a light inextensible string of length 67 5 cm are placed on a smooth horizontal surface With what minimum velocity u in m s should the ball B be projected vertically upwards so that the ball A leaves the horizontal surface g 10 m s

Vernier calipers can be used for measuring volume of a small right circular uniform hollow cylinder External diameter and total height can be measured by lower Jaws Internal diameter and depth can be measured by using upper jaws and stem respectively Stem is a thin rod which is fixed with Vernier scale and slides over main scale along with Vernier scale In a Vernier calipers when zero of main scale coincides to zero of Vernier scale lower jaws are open upper jaws are perfectly closed can end of stem lies left to the right most end of main scale Select the correct option s A In internal diameter measurement there is no zero error B In external diameter measurement there is a negative zero error C In depth measurement there is a positive zero error

Question No 12 A non conducting solid sphere of radius r 0 5 m and mass m 2 5 kg has a charge of Q 10 C distributed uniformly over its volume If the sphere is rotated about a diameter with an angular speed of w 25 rad s Find the magnetic moment in Am and angular momentum in kgm s of the solid sphere m 0 r Solid sphere xo X X A W

m Three blocks A B and C of mass m and m of different densities and dimensions are placed over each other as shown in the figure The coefficients of friction are shown Blocks placed in a vertical line are made to move towards right with same velocity at the same instant Find the time in sec taken by the upper block A to topple from the middle block B Assume that slipping at any surface don t stop before A topples from B w 4 A A I L 2 g 4L L 4 L 2 B L 2

Consider a fluid in a container Let the density of the fluid at the surface and at depth Po H be p and prespectively The bulk modulus of the fluid is Bo If p then the constant a is Assume P Po 1 Po 1 apgH

22 A non uniform disc of mass m and radius R hinged at some point and performing pure rotation with respect to hinge in horizontal plane with an angular velocity At certain instant center of the disc is at origin in the mentioned co ordinate system and velocity of particle As R VA 31 41 m s Choose the correct options A Velocity of particle B at the given instant is 3R C Co ordinates of hinge is 3 0 D Co ordinates of hinge is 0 B B Velocity of centre of disc at the given instant is 3R 4 A 70R 4 30R 1

The figure shows a hollow circular tube fixed to a frictionless horizontal table It is the top view of the arrangement A ball is shot into end A of the tube to leave the other end B at high speed The ball s diameter is slightly less than the internal diameter of the tube Which of the paths below will the ball follow on the table after it leaves the tube O A C

A car starting from rest accelerates at the rate f through a distance S then continues at constant speed for time f t and then decelerates at the rate to come to rest If 2 the total distance traversed is 15 S then 2 1 S n A 2 72 3 S 2 S 1 ft 4 4 S 5 f 1 ft

A block of mass m 1 kg is placed on a smooth surface and is connected with a spring of spring constant k 100 N m and another end of spring is connected to a fixed wall as shown The block is pulled by a distance A 0 10 m from its natural length and released at t 0 m 1 0kg 1 K 100N m 000000 smooth TC A The maximum speed is after t 20 S C Time taken to cover first 0 05 m t TC 40 S o 0 1m B Time taken to cover first 0 10 m t 70 20 D Time taken to cover first 0 05 m t TU

The focal length of the objective and eye lens of a microscope are 4cm and 8cm respectively If the least distance of distinct vision is 24cm and objective lens then the magnifying power of the microscope will be SKIPPED

llustration 22 The figure shows one end of a string being pulled down at constant velocity v Find the velocity of mass m as a function of x lution Using constraint equation 2 x 6 y length of string constant Differentiating w rt tima Newton s Laws of Motion b11b m X

No 38 View In English A particle of small mass m is joined to a very heavy body of mass M by a light string passing over a light frictionless pulley Both bodies are free to move The total downward force on the pulley is approximately 2 3 Correct Answer 4 Our Answer 2 atus incorrect 2 mg Mg 4 mg 4 Mg Close mo V

b The resistance of colour code red black red and g is connected in parallel with a resistance of col code red green brown and gold again in series w green orange red and silver What is the possil colour code of bands a b c and d for the equivale resistance 90 P

25 For a particle moving on a straight Vine the variation of its acceleration a as a function of time t is as shown 0 Variation of its position x with time it is best

A body moves along a path PQR from P to R shown as a dashed line in figure When the particle is at Q its speed is decreasing The acceleration of the particle at Q is best represented by the 0 1 02 03 04 2 1 K P 3 11 R

Three blocks A B and C of mass m 2 and m of different densities and dimensions are placed over each other as shown in the figure The coefficients of friction are shown Blocks placed in a vertical line are made to move towards right with same velocity at the same instant Find the time in sec taken by the upper block A to topple from the middle block B Assume that slipping at any surface don t stop before A topples from B 1 4 O ug 2L ug 14 B 1 1 2 C

4 y ax b sin cof kx 3 The equation of standing wave in a stretched string TEX is given by y 5 sin cos 40st where x and y are in cm and t in second The separation between two consecutive nodes is in cm 1 1 5 2 3

View In English A sphere of radius 10 cm and density 500 kg m3 is under water of density 1000 kg m3 The acceleration of the sphere is 9 80 m s2 upward Viscosity of water is LO centipoise If g 9 81 m s2 the velocity of the sphere is 0 rect Answer 3 Answer 1 us incorrect 9 m s 10 m s 11 m s 12 m s

A particle starts moving with velocity v i m s and acceleration a 1 i m s2 Find the radius of curvature of the particle at t 1 sec 05m O 5 5 m 06 5m O None of these

In order to increase the capacity of a parallel plate condenser one should introduce between the plates a sheet of assume that the space is completely filled A B C Mica Tin Copper K YOU MARKED

A progressive wave is represented by y 2 sin 100ml 2xx where x and y are in cm and is in second The maximum particle velocity and wave velocity respectively are INCERT XI Pg 373 1 628 cm s 628 cm s 2 50 cm s 50 cm s 3 628 cm s 50 cm s 4 50 cm s 628 cm s

gh ge 5 64 a What is the magnetic flux through one turn of a solenoid of self inductance 8 0 10 5H when a current of 3 0A flown through it Assume that the solenoid has 1000 turns and is wound from wire of diameter 1 0mm b What is the cross sectional area of the solenoid Ans a 2 4 x 10 7Wb b 6 37 10 5m

In the figure find the minimum value of mass m in kg of the rod so that the block of mass M 12 kg remains stationary on the inclined plane take g Assume there is no friction between rod and block 37 rod m M 0 5 10 m s

The resultant of three vectors of magnitude 1 2 and 3 units whose directions are along the sides of an equilateral triangle in same order is at an angle of A 300 with the first vector 6 150 with the first vector B D 1000 with the first vector 2100 with the first vector

Q No 43 3 4 View In English A pump is used to deliver water at a certain rate from a given pipe To obtain water 2 times in the same time the power of the pump has to be made 2 times 4 times 8 times 16 times Correct Answer 3 Your Answer 2 Status incorrect Complete Question Content Add to Bookmark List 200 Close

In which of the following situations the weight reported by a weighing machine inside the elevator will be greater than the true weight of the body Elevator speeding up in upward direction Elevator speeding up in downward direction Elevator moving up with constant speed Elevator moving down with constant speed

A ball initially moving towards east with a speed 10 m s changes its direction of motion towards north keeping speed constant in 2s The magnitude of average acceleration is O 10 2 m s O 5 m s 10 m s O 15 m s

4 45 A circular loop of radius 15 7cm carries a current of 15A Another loop of radius 1 57cm having 30 turns is placed at the center of the larger loop and a current of 1A is passed through it What torque acts on the small loop if the planes of two loops are at right angles and the induction due to large loop is considered uniform throughout the area of smaller loop A 0 57 10 Nm B 1 13 x 106 N m D 2 26 x 106 N m C 114 x 10 6 Nm

8 Imagine a current carrying wire with the direction of current downward or into the page The direction of magnetic field lines is 2013 1 a clockwise c into the page b anti clockwise d out of the page

An electron is accelerated from rest through a potential difference of 75 V What is its final speed m 9 1 10 31 kg qe 1 6 10 O 7 2 x 100 m s O 4 6 x 106 m s O 5 6 x 106 m s O 5 1 x 10 m s

6 An iron bar of conductivity K 79 W m K 1 and an identical brass bar of conductivity K 109 W m 1 K 1 are soldered end to end The free end of iron and brass bars are maintained at 400 K and 300 K respectively What is temperature of junction of two bars NCERT Pg 292 1 350 K 2 342 K 3 333 K 4 305 K

3 5000 Hz 4 3000 Hz A source of frequency v gives 5 beats second when sounded with a source of frequency 200 Hz The second harmonic of frequency 2v of source gives 10 beats second when sounded with a source of frequency 420 Hz The value of vis 1 205 Hz 2 195 Hz 3 200 Hz 4 210 Hz

An inflated rubber balloon contains one mole of an ideal gas has a pressure P volume V and temperature T If temperature rises to 1 1 T and volume increases to 1 05 V finall pressure will be NCERT Pg 322 1 1 1 P 2 P 3 Less than P

8 A sound source is moving towards a stationary observer with 1 10 of the speed of sound The ratio of apparent to real frequency is 1 6 10 9 10 2 11 10 10