Basic Physics Questions and Answers

The focal lengths of the objective and eye piece of a compound respectively microscope are 2 cm and 3 cm The distance between the objective and eye piece is 15 cm The fina image formed is at infinity The distances in cm of object and image from objective are 1 2 4 and 12 2 2 4 and 15 3 2 4 and 3 0 4 2 3 and 12 OPTICAL INSTRUMENTS

B A barometer is constructed using a liquid density 760 kg m What would be the height of the liquid column when a mercury barometer reads 76 cm density of mercury 13600 kg m 1 13 6 m 2 136 m 3 0 76 m 4 1 36 m

Find the current flowing through R in the circuit below assuming the diodes to be ideal R V 10V O Zero O 0 5 mA O 1 MA O 2 MA R ww R R 10KQ R 5KQ R 5K0

Jestion 33 ra ladder resting against a wall and floor ving a weight of W N the direction of ction offered by the wall will be owards the wall way from the wall wards the floor way from the floor

Question 23 Identify the force system shown in following figure Note Click on image to enlarge it Co planar non concurrent Co planar concurrent Non co planar concurrent Non co planar non concurrent

Question 35 A simply supported beam of span 4m is subjected to an anticlockwise couple of 100kNm at the center of the beam The vertical reaction at the LHS Left Hand Support will be 25KN 50KN 100kN 75kN

Question 6 Following figure shows coplanar concurrent force system Calculate summation of resolved vertical components of all forces Fy Note Click on image to enlarge it Snow 102 49 N 102 49 N 129 29 N 129 29 N 100 N

Consider a hypothetical situation where electromagnetic interactions between the charges do not exist In such a situation which of the following would not be possible 1 Sitting on a chair 2 Holding a pen 3 Climbing stairs 4 All of the above

NEET PHYSICS Q 95 The gravitational force between a point like Q 95 mass M and an infinitely long thin rod of at perpendicular linear mass density distance L from M is MG L 2MGX 1 All India Major Test Series Phase I II Major Test 27 21 28 05 2020 fan 1 MGA 2 L 4 infinite 2 en 1 1 3 MGA L 2MGA L L 2 1 MG 2 L 4 311

167 A compound microscope has an objective lens with a focal length of 1 5 cm and an eye piece of focal length 5 cm It is focussed on an object which is at a distance of 1 8 cm The length of the microscope for normal adjustment is 1 14 cm 2 4 cm 19 cm 4 8 5 cm

particles having masses 2 kg and 4 kg If the first particle is pushed towards the centre of mass through a distance 4 m The distance through which the second particle be moved so as to keep the centre of mass at the same position is 1 4 m 3 2m 2 1 m 4 zero 2 kg 4 kg 1 4 m 3 2m 4 m cu a face fa f I 2 1 m 4

Q 91 0 92 In the arrangement shown in the figure the Q 91 force of friction acting between the two blocks is 1 8 N 3 6 N 20 N Frictionless 2 kg PHYSICS 4 kg F 2N H 0 5 2 10 N 4 4 N An obiect is thrown from a point A Q 92 faafia en F 20 N 1 8 N 3 6 N m Frictionless 2 kg 4 kg F 2N H 0 5 2 10 N 4 4 N 345 FOR OR OR A

MATCH Answer the following by appropriately matching the list based on the information given in the paragraph A Block of mass m is placed on a fixed incline of inclination and the coefficient of friction between the block and the incline is List I gives different possible values of 0 and list II gives different magnitudes of some quantity List I List II 1 II III IV 30 37 45 60 P Q R S T U A I P II R III U IV T B I P II Q III R IV T C I T II S III R IV P 1 2 3 5 1 2 4 5 3 2 If 0 then the normal reaction on the block in units of mg will be given by Options m

5 7 A thin uniform rod AB of mass m and length is rigidly attached at its midpoint to a rigid rotation axis 00 as shown in figure 5 136 The axis is set into rotation with constant angular velocity o Find the resultant moment of the centrifugal force about the point C where the rod is attached to the axis The inclination of the rod AB to the axis of rotation O0 is 0 44 dm M dx 11 da C A O 0 B F om OC wa Q dy dm lla wa Figure 5 136

Question 23 In a certain machine 120 N load is lifted by an effort of 8 N at an efficiency of 75 Calculate the load lost in friction 160 N 120 N 20 N 40 00 N

Note Click on image to enlarge it 80N 100N 59 85 N 34 98 N 34 98 N 15 45 30 SON X60 N

is placed just in the middle between two long fixed the charges of charge density each in a gravity free space The wires are in the x y plane Which of the following statement is wrong 1 1 The equilibrium of the electron will be unstable along x direction 2 The equilibrium of the electron will be stable along z axis The equilibrium of the electron will be neutral along y axis The equilibrium of the electron will be stable along y axis near charge density 39 I 2

0 49 A simple pendulum bob is suspended with the help of a string of length If at its equilibrium position bob is imparted a velocity v 3ge then the angle with vertical at which the pendulum bob will discontinue the loop is tan xo 2 Find xo

Q 34 A proton beam enters a uniform magnetic field of 0 3 Tesla making an angle of 609 to its direction with a velocity of 4 x 105 m s The radius of the helical path of the proton beam will be A 4 mm B 6 mm C 8 mm D 12 mm Q 35 There is a magnetic field acting in a plane downward perpendicular to sheet of paper Particles in vacuum

The incorrect statement among the following is O O O The first ionisation potential of Al is less than the first ionisation potential of Mg The second ionisation potential of Mg is greater than the second ionisation potential of The first ionisation potential of Na is less than the first ionisation potential of Mg The third ionisation potential of Mg is greater than that of Al

The resultant of two concurrent forces which are acting at an angle 9 is given by O P2Q2 2PQCose P2 Q 2PQCos 0 P2 Q 2PQ Sing P2 Q 2PQ Sing

Question 19 A screw jack lifts a load of 30 KN by an effot of 400 N applied at the end of handle of 80 cm If the pitch of screw is 20 mm calculate efficiency of the machine 2 98 20 48

An isolated conducting hollow sphere of radius r 5 m is charged to a potential V 10 volts a What is the charge stored in the sphere b How would your answer differ if the sphere was solid A plane parallel capacitor consists of two metallic plates of area A 2 m2 each separated by a d

In a uniformly charged ring of total charge Q and radius R the electric potential V is plotted as function of distance r on its axis from the centre The graph which would correspond to the above will be 1 2 3 4 Jan R O V R

2 Locate the position of the point or points at which the electric field strength is zero 5q 29

glas 125 An object O is placed on one index 1 5 as shown Separation between the slabs slabs A and B of thickness 1 5 cm and refractive is 1 5 cm The position of image of O when viewed from the other side of slab B will be 1 5 cm 14 A B 2 cm 4 1 5 cm 1 1 cm toward the slab A K 1 5 cm Observer 2 1 5 cm away from the slab A 3 2 cm toward the slab A 4 2 5 cm away from the slab

A solid cylinder of mass m is rotating with angular velocity about its fixed axis of symmetry It is brought in contact with a plank of mass m placed on a smooth surface There exist friction between cylinder and plank because of which planik starts moving After some time plank moves such that the there is no slipping between cylinder and plank Rough surface 8 Smooth surface The final velocity of the plank when there is no slipping between cylinder and plank is 2Ro 3RD Reg C D Rig 2 Select correct statements A magnitude of angular impulse imparted to the cylinder during this process 8 magnitude of angular impulse imparted to the cylinder during this process C the total work done by friction force in this process R D the total work done by friction force in this process mRu mR 2mR 3

iii In electrostatics scalar potential v ax 5x then what is the value of the volume charge density Here a is constant fenfa fa f x 5x BADI

143 A plane mirror is placed on x z pla to rotate about z axis A fixed object is on x y plane at a point O 5 m 5 m When mirror starts rotating anticlockwise with angular speed 5 rad s about z axis The initial linear speed of image is YA 1 25 m s 3 50 m s 0 5 m 5 m X 2 25 2 m s 4 50 5 m s

c If x a find the potential energy of a unit charge kept at that position Four charges of magnitudes q but may have different sign each are placed in the corners of square of side length a such that the field at the center is zero Find all possible values of th electrostatic potential energy of the system An isolated conducting hollow sphere of radius r 5 m is charged to a potential V 10 volts

1 43 The current velocity of a river grows in proportion to the distance from its bank and reaches the maximum value v in the middle Near the banks the velocity is zero A boat is moving along the river in such a manner that it is always perpendicular to the current and the speed of the boat in still water is u Find the distance through which the boat crossing the river will be carried away by the current if the width of the river is c Also determine the trajectory of the boat

Four charges qqaq are kept fixed at point a 0 a 0 0 a and 0 a The motion of the fifth positive charged particle kept at origin is simple harmonic motion when given very small displacement is 1 Along x axis 2 Along y axis 3 Along z axis 4 Both along x axis and y axis

b Determine two least possible thicknesses of a film to be coated on a glass surface 1 54 such that no normally incident light of wavelength 540 nm is reflected

b A 100 m long optical fiber having a core diameter of 20 m and refractive index of 1 55 is used in signal transmission If a ray of light is incident on one end of the optical fiber at an angle of 40 how many reflections does it undergo to reach the other end

48 A particle of mass m 1 kg is suspended by a string of length 5 meter horizontal velocity vo is imparted to it suddenly When the string is horizontal the acceleration of the particle is inclined to the string by 45 find vo in m s 6

Question 6 A Weston s diffrential pulley block has 12 cogs on smaller pulley and 13 cogs on bigger pulley On this machine a load of 7 8 KN is lifted by an effort of 750 N Calculate efficiency of machine at this load 80 20 30

Question 22 The ratio of the limiting force of friction F max to the normal reaction R is known as Angle of friction Modulus of elasticity Angle of repose

i If relative magnetic permeability of magnetic substance is 1 04 What is the value of magnetic susceptibility of the material fra 1 04 af In electrostatics scalar potential y ax 5x then what is the value of the

Question 36 A stone having the weight of 500N is at the top of a hill surface making an angle of 200 with the horizontal if the coefficient of friction for the hill surface is 0 300 then stone will be stable stone will be unstable can t say stability will depend on the weight of the stone

for laminar flow of liquids through pipes the ratio of the maximum velocity and the average velocity is O 0 5 for newtonian liquids O more than 2 for pseudoplastic liquids O less than 2 for dilatant liquids O equal to 2 for newtonian liquids

144 Light ray is incident at an angle of 60 on face of a rectangular prism of refractive angle 90 If light ray grazes the second face then the refractive index of material of prism is 1 3 325 2 2 2 7 2 4

Assume that the nuclear binding energy per nucleon B A versus mass number A is as shown in the figure Use this plot to choose the correct choice s given below BA 6 4 2 100 2 00 A A Fusion of two nuclei with mass numbers lying in the D B Fusion of two nuclei with mass numbers lying in the C Fission of a nucleus lying in the mass range of 100

A wire loop is rotated in a magnetic field the frequency of change of direction of induced emf is 1 Thrice per revolution 2 Twice per revolution 3 Six times per revolution 4 Four times per revolution

101 tuning forks are arranged in increasing order of frequency highest frequency being thrice that of lowest frequency When any two consecutive forks are played beat frequency produced is 2Hz Frequency of 10th tuning fork is

43 A projectile is fired at speed vo and angle 0 If the radius of curvature at the top equals half the maximum height as shown in figure Find the value of sec 0 A pendulum of length I E

70 Ray Optics and 54 A converging beam of light forms a point image on a screen of an object A plane glass plate of 3 2 2 1 5 cm 4 1 33 cm is thickness 2 cm and refractive index introduced in the path of the beam The screen should be shifted w r t its initial position to obtain point image on screen will be 1 3 cm 3 0 67 cm 3X

A body is moving along the circumference of a circle of radius R and completes half of the revolution Then the ratio of its displacement to distance is 1 2 2 2 1 3 2 4 1 2 A body completes one round of a circle of radius R in 20 second The displacement of the body after 45 second is 2 2R R 1 1 V V 2 3 2 R If a body covers first half of its journey with uniform speed v and the second half of the journey with uniform speed v 1 then the average speed is 2 AVIV 3 V V2 1 4 2R 4 12 12

EMENT 1 A particle is projected from origin under gravity with the angle of projection 0 tan 2 The radius vector locating highest point is at an angle of elevation and T 4 2 X S Vous STATEMENT 2 The ratio of average velocity to the velocity of projection is not necessarily greater than unity for the particle projected under gravity at come angle from horizontal

Column A 1 Lubrication 2 Contact force 3 Non contact force 4 Disadvantages of friction 5 Advantage of friction Column B a Wastage of energy b Magnetic Force c Decreases friction d Sewing clothes e Muscular force

A body of mass m is given a minimum velocity when it enter the vertical loop of radius R so that it can just complete the circle The velocity of the body when it will be in its horizontal position is 1 gR 3 2gR 2 3gR 4 4gR