Basic Physics Questions and Answers

40 A mirror produces on a screen an image of the sun 2 cm in diameter If the sun s disc subtends an angle 0 1 radian on the surface of the earth then the radius of curvature of the mirror will be 36 10 5x0 For To 1800 1 20 cm 3 200 cm 40 cm 4 400 cm

A bob of mass m 10 kg hangs by a light inextensible string which is connected with a rigid support after passing over a smooth pulley P If the bob is released from an angular position 0 30 at the given pc P The force exerted by the string on the pulley is 50 3N The net horizontal force exerted by the string on the mass is 25 3N The force exerted by the string on the wall is 50 3N Acceleration of the bob at given instant is zero

In the above figure a block of mass m is given a initial velocity v A force acts on m in negative direction Magnitude of force F um Which of the graph shows correct variation of velocity with time SolveLancer Test a b O d a b 0 m V ve

If an object is moving at constant acceleration in a straight line its instantaneous velocity half way through any time interval is 2 1 greater than its average velocity less than its average velocity equal to its average velocity 9 64 3 bu 4 half of its average velocity 942 5 000 8 3 5

If an emitter current is changed by 4 mA the collector current changes by 3 5 mA The value of will be 1 0 5 3 0 875 7 Correct Answer 1 Status unattempted 4 3 5

Two blocks A and B each having a mass of 480 gm connected by a light string passing over a smooth light pulley The block A is attached to a spring of spring constant 60 N m whose other end is fixed to a support 40 cm the horizontal surface as shown Initially the spring is vertical and unstretched when the system is released to move Find the velocity of the block A at the instant it just breaks off the surface below it take g 10 m s 154 m s 1 44 m s 1 34 m s O 164 m s eeeeeeeee m m B

5 The temperature of sink of Carnot engine is 27 C Efficiency of engine is 25 Then temperature of source is uchun f25 1 227 C 2 327 C 3 127 C 4 27 C

500 A particle is projected with speed u at an angle 8 with the vertical Change in speed of the particle when it reaches the highest point of trajectory from starting point will be ucose 2 usine 3 u cose 1 4 u sine 1 72 m

1 A boat having length of 2 5m and breadth 2m is floating on a lake The boat sinks by 1cm when a man gets on it The mass of the man is 2 5m2m Ich fan 34 dl da te 1 cm gam 1 50 kg 2 60 kg 3 62 5 kg 4 70 kg

In the arrangement shown in the figure mA 1 kg and me 2 kg while all the pulleys and the strings are massless and frictionless At t 0 a force F 10 t starts acting over central pulley in the vertically upward direction The velocity of A in m s when B loses contact with floor will be F 10t o G

Board 5 In the given LR circuit switch S is closed at t 0 The energy stored in the magnetic field 3L at time to In2 is 2R 1 2 S V L 4R V L L R L reellee 2 4 V L 2R 2R V L PA6 24 HOM

2 It is given that angular momentum of an electron in a particular orbit of hydrogen like atom of atomic number Z is L Assuming Bohr s model and angular momentum quantisation to be true what will be magnitude of total energy of electron for this particular orbit 1 3 m2 e4 32n L 2 2 m22 2 4 m2 87 32 m z 4 8 32 37

3 Two immiscible liquids of density 4 gm cm 6 gm cm are mixed such that their volumes are same What will be density of mixture A B C D 4 gm cc 5 gm cc 6 gm cc 7 gm cc

Is given that g H Hz Find angle made by the ray of light with the normal in medium of refractive index 3 1 i 3 sin sini LL Air air H H3 2 sin 4 sin sini Hy sini

When light of maximum wavelength 300 nm falls on a photoelectric emitter photoelectrons are liberated For another emitter however light of maximum wavelength 600 nm causes photoelectric emission The ratio of work functions of first emitter to second emitter will be 1 2 2 1 1 1

A body covers half of its journey with speed 20 km h and rest half of its journey with 40 km h What will be the average speed of this journey 320 km h 40 km h ad du al 1 36 66 km h 2 26 66 km h 3 30 km h 4 35 km h ZIEI

7 A wire has a mass 0 3 0 003 g radius 0 5 0 005 mm and length 6 0 06 cm The maximum percentage error in the measurement of density is 0 3 0 003 g 6 0 06 cm 14 1 1 2 2 0 5 0 005 mm 3 3 4 4

The electric resistance of a certain wire of iron is R If its length and radius are both doubled then 1 The resistance will be doubled and the specific resistance will be halved 2 The resistance will be halved and the specific resistance will remain unchanged 3 The resistance will be halved and the specific resistance will be doubled 4 The resistance and the specific resistance will both remain unchanged 1 2 3 4

If the kinetic energy of a body is increased by 300 its momentum will increase by 1 100 150 200 400 3 Correct Answer 1

7 The charge flown through a circuit in the time interval between t and t dt is given by dq e t dt where is a constant Find the total charge flown through the circuit between t 0 to t t

Consider a unit cube which is acted upon by an equal tensile force of F on all the six surfaces of the cube The increase in the length of each side is F xoF fount to be where Y o are Y Y Young s modulus and Poisson s ratio respectively Now Find the value of X 6 Correct Answer

4 A bucket tied at the end of a 1 6 m long string is whirled in a vertical circle with con stant speed What should be the minimum speed so that the water from the bucket does not spill When the bucket is at the highest position Take g 10 m sec A 4 m sec B 6 25 m sec C 16 m sec D None of the above

Abattalion of soldiers is ordered to swim across a river 500 m wide At what minimum rate should they swim perpendicular to river flow in order to avoid being washed away by the waterfall 300 m downstream The speed of current being 3 m sec A 6 m sec B 5 m sec C 4 m sec D 2 m sec

For four particles A B C D the velocities of one with respect to other are given as Voc is 20 m s towards north VBC is 20 m s towards east and VBA is 20 m s towards south Then VDA is A 20 m s towards north B 20 m s towards south D 20 m s towards west C 20 m s towards east

7 If the speed of light were 2 3 of its present value the energy released in a given atomic explosion will be decreased by a fraction m 2 C mc 2 a 2 3 c 3 4 b 4 9 d 5 9 E m AE S mc 9 10 dous The time

Numerical Value Type Read More Network shown in the figure is part of a circuit The current is 2 A and is decreasing at the rate of 2 A s

15 Charge is distributed inside a long cylindrical volume of radius R such that charge density inside the volume varies as where a is a constant and r the distance from the axis of the cylinder If the magnitude of electric field inside the cylinder is independent of r the value of n is

State the representation with no spaces between numbers A Question 8 1 point What is the decimal representation value of the binary number 101101

SolveLancer Test Consider the following statements given below and answer the correct 1 For a system of particles the sum of momentum and the sum of kinetic energy of particles as seen from frame of reference of centre of mass of the system are both zero II In a binary star system the lighter star revolves around the heavier star due to gravitational force III For a wave produced in the medium the amplitude and frequency and wave velocity depend on the source IV Electric field are always conservative in nature SolveLancer Test a 1 b 2 c 3 d 4

106 Electromagnet 8 An inductor L and a resistance R are connected in series with a battery of emf E and a switch Initially the switch is open The switch is closed at an instant t 0 Select the correct alternatives 1 At t 0 induced emf in inductor is zero L 2 At t energy stored in the inductor is R 2 LE 2R 2 1 e 3 At t R 4 At t R E 1 1 induced emf in the inductor is E e voltage drop across the resistor is

51 If and be the wavelength of first Balmer line of deuterium and hydrogen respectively then un am a va di un ar to 1 H 2 H 3 H 4 2D 2 H 52 A parallel plate capacitor after charging is kept connected to a battery and the plates are pulled apart with

54 The current i in a induction coil varies with time t according to the graph shown fayd er i et nyt ada di which of the following graph shown the induced emf E in the coil with time A 1 i E KELU 3 2 t 4 t

26 A small circular flexible loop of wire of radius R carries a current It is placed in a uniform magnetic B The tension in the loop will be doubled if 1 is doubled 3 R is doubled 7 Two circular coils mounted parallel to 2 B is doubled 4 All of these 11

Potential energy function along x axis in a certain force field is given as x3 5 U x 6x 6 3 2 For the given force field choose the correct option s 1 the points of equilibrium are x 2 and x 3 the point x 2 is a point of unstable equilibrium the point x 3 is a point of stable equilibrium Othere exists no point of neutral equilibrium

The displacement of a particle is rep resented by the following equation s 3t 3 7t 2 5t 8 Where x is in meters and t in second s The acceleration of the particle at t 1 s is IN this question i dint understand th e part that how 9t 2 14t 5

Find the voltage across 4 resistor for the circuit shown in figure 1002 www 1522 E 25 V www 492 602 www 892 Only one correct answer 852

A conducting spherical shell is given charge 20 A point charge Q is kept inside the shell at point O as shown Now if charge Q is shifted from point O to point P then magnitude of electric field at point A outside the shell will 2Q Q D A

Apparent dip at a place is always greater than or equal to the value of true dip at that place This is due to 1 Increase in apparent value of B 2 Decrease in apparent value of B 3 Increase in apparent value of B 4 Both 1 2

A body is thrown vertically upward its velocity and acceleration at top respectively are 0 0 0 g 0 g g g A body is projected vertically up from ground neglecting air friction Which of the graph best shows the variation of speed v with time i 2 1

Two planets have masses M and 16 M and their radii are a and 2a respectively The separation between the centres of one planets is 10a A body of mass m is fired from the surface of the larger planet towards the smaller planet along the line joining their centres For the body to be able to reach at the surface of smaller planet the minimum firing speed needed is GM GM2 B A 2 C a 3 5GM D 4 ma GM

A magnet when suspended at an angle of 30 to magnetic meridian the dip needle makes an angle 45 with horizontal The dip angle measured in magnetic meridian will be O 1 tan 3 tan 1 3 1 2 tan 3 3 2 8 Pusa Road New Delhi 110005 Ph 011 47623456 2 3 4 tan 1

3 As shown in figure the key K is closed the direction of the induced current in the coil B will be A O B In 1 clockwise and momentary 2 anticlockwise and momentary 3 clockwise and continuous 4 anticlockwise and continuous K

Q4 The refractive index of vitreous humor in our eye ball is 1 34 Visible light of wavelength ranges from 402 rim to 670 nm as measured in air The wavelength range just approaches retina within vitreous humor is O A 280 nm to 480 nm O B 300 nm to 500 nm O C 340 nm to 540 nm O D 320 nm to 520 nm

A Ball coming back to Projection Point A ball is projected with a velocity u at an elevation from a point distance d from a smooth vertical wall in a plane perpendicular to it After rebounding from the wall it returns to the point of projection If e is the coefficient of restitution between ball and wall find the maximum distance d for which ball will come back to the projection point

Seven resistor are connected as shown in circuit The equivalent resistance in ohms of this network between A and B and a fa A 7B H87 H Y G 3 NH N G 1 6 A 2 8 1002 wwww 300 www www 602 80 www www 402 www 1002 3 12 www B 892 4 20

3 1 Two parallel plate capacitor of capacitance 2C and Care charged to the potentials 2V and V respectively and are connected in a circuit along with a resistance R as shown in the diagram The switch k is closed at t 0 Find the current in the circuit as a function of time and total heat produced in the circuit SR 2C 2V F F C V Figure 3 372 k

A block of mass m initially at rest is dropped from a height h on to a spring of force constant k The maximum compression in the spring is x then mgh kx 2 mg h x kx 2 mgh k x h 2 mg h x k x h 2

marks A train starts from rest at t 0 along a straight track with a constant acceleration of 5 m s A passenger at rest in train observes a particle of mass 1 kg on the floor with which it has a coefficient of friction us Uk 0 6 Att s a horizontal force F 13 N is applied on the particle for 2s duration The passenger observes that the particle is now moving in a perpendicular direction of motion of the train g 10 m s 5 1 13 The magnitude of acceleration of the particle with respect to the ground at t 5 sec is 61 m s with the direction of motion of the train The direction in which force F 13 N is applied is at cos The momentum of the particle at t 6 sec with respect to the train is 12 kg m s The momentum of the particle at t 6 sec with respect to the train is 6 kg m s

apan ne 2 303 nRT log V2 V1 ye kyu nahi use kiya Iska sahi ans PV se aara h Ka Under isothermal condition a gas at 300 K expands from 0 11 to 0 25L against a constant external pressure of 2 bar The work done by the gas is Given that 1L bar 100 J 1 30 J 2 5kJ 3 25 J 4 30 J A compound is formed by cation C and anion A

13 If a nucleus is emitting e particle its neutron to proton ratio will eff 1 increase 1 G n 2 decrease 2 Pr 3 remain unchanged THIG FE 4 can t be determined He 4