Basic Physics Questions and Answers

6 1 At what distance from the center of the earth will a 1 kg object have a weight of 1 N If released from rest at this distance what will its initial acceleration be Ans 2 023 107 m

3 a 3 Person A is moving towards west with speed 3 km and B is moving towards north with speed 4 km h Then the velocity of A relative to B is at an angle of 1 37 south of east 3 53 south of west Por 8 Runo R 2 30 south of west 900 of west 4 53 west of south 47623458

9 Consider the following gram I 1 gram of water at 100 C and 1 of steam at 100 C contain same amount of heat II 1 m of dry air is heavier than 1 m of humid air III Density of a substance in CGS system is numerically equal to its specific gravity Which of the statements given above is are correct A I only C I and III B III only D II and III

gram 59 Consider the following statements I 1 gram of water at 100 C and 1 of steam at 100 C contain same amount of heat II 1 m of dry air is heavier than 1 m of humid air system III Density of a substance in CGS is numerically equal to its specific gravity Which of the statements given above is are correct A I only C I and III B III only D II and III

Aakash Institute 35 If E and E are the magnitude of electric field the axial and equatorial points due to a sh electric dipole then the correct relation is 1 Eq 2E 3 E E 2 2E E 4 None of these

G L Fig 3 19 the triangles C OQ and C OR are similar OC C Q1 OC C R 12 OC C B OC C A C B OC C A OC OB OA Q ri r 1 BO r C B r C A 72 So the point O divides the thickness of the lens AB in a fi atio i e in ratio of the radii of curvature of the two surfaces Again OB OA OB OB OA OB A OB t me from

uniform magnetic field B exists in the region between x 0 and x Q and momentum p directed along x axis enters region 2 from region 1 at point P y R Which of the following option s is are correct egion 1 Region 2 Region 3 X O Q y R D For B X X X W For B B 3R 2 When the particle re enters region 1 through the longest possible path in region 2 the magnitude of the change in its linear momentum between point P and the farthest point from y axis is p 2 8p 13 QR P 3R region 2 in the figure pointing normally into the plane of the paper A particle with charge 2 the particle will enter region 3 through the point P on x axis 2 p 3 QR For a fixed B particles of same charge Q and same velocity v the distance between the point P and the point of re entry into region 1 is inversely proportional the particle will re enter region 1 54 1 6 11 16 21 26 31 36 41 46 Not Answered 2 7 12 17 22 27 32 37 42 47 8 13 18 23 28 33 38 43 48

Electric Charges and Fields 58 A small dipole of dipole moment P is kept at the centre of a ring of radius R and charge Q The dipole moment has direction along the axis of ring The resultant force on the ring due to dipole is 1 Zero 2 KPQ R

5 If mass energy equivalence is taken into a when water is cooled to form ice the mass of water should A increase B remain unchanged C decrease D first increase then decrease LEFF 2002

5 A gun of mass 10 kg fires 4 bullets per second The mass of each bullet is 20 g and the velocity of the bullet when it leaves the gun is 300 m s The force required to hold the gun when firing is a 6 N b 8 N c 24 N d 240 N

The boiling point mercury thermometer can be used to 367 C mean a temperature of 500 C A by filling the space above mercury w oxygen at high pressure B by filling the space above mercury w nitrogen at low pressure C by filling the space above mercury wit nitrogen at high pressure D by keeping space above mercury a A M U Med 2003 vacuum

An electron moves in a circular orbit of radius 0 53 A with a speed of 6 28 x 106 m s What is the equivalent current in the orbit t 2a a 3 mA c 2 mA b 4 mA d 1 mA I av 273

38 On each of the three corners of an equilateral triangle of side D three equal charges Q are placed The coulombic force experienced by one charge due to the other two charges is 1 Zero 3 3Q 4TE 0 2 2 2Q 4 TED 2Q 4TE D Telegram ne

A swimmer reaches the other bank of a flowing river exactly opposite to the starting point If he was swimming at 2 km hr while maintaining 150 with the flow then time taken by him to cross the river 1 km wide is 1 30 min 3 2 hrs A bus with a vertical wind shield moves horizontally at a speed of 40 km hr while rain is falling vertically at a speed of 30 km hr The angle at which rain drops strike the wind shield is 2 45 4 30 1 37 3 53 2 1 hr 4 20 min

But currents are not always ste Medical CAREER INSTITUTE Path to Success ROTA RAJASTHAN ation 4 Current through a wire decreases from 4 A to zero in 10 sec Calculate charge flown through the wire during

A block of mass m is attached to a massless spring having a spring constant k The other end of the spring is fixed from the wall of a trolley as shown in the figure Spring is initially unstretched and the trolley starts moving toward the direction shown Its velocity time graph is also shown Smooth m k vvvvvvv Motion 7777777 Je 0 37

A A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path Such a device is used in medical laboratories for instance to cause the more dense red blood cells to settle through the less dense blood serum and collect at the bottom of the container Suppose the centripetal acceleration of the sample is 2 83 x 103 times as large as the acceleration due to gravity How many revolutions per minute is the sample making if it is located at a radius of 2 00 cm from the axis of rotation

4 92 Two balls of masses m and 2m are suspended by two threads of same length and from the same point of a ceiling The ball m is pulled aside through an angle a and released from rest after a tangential velocity vo towards the other stationary ball is imparted to it To what height will the balls rise after collision if the collision is perfectly elastic Ans h 18g v 2g 1 cosa h 4 18g v 2g 1 cosa F

lustration 7 Find free electrons per unit volume in a metallic wire of density 104 kg m af and number of free electron per atom is one olution NAXM No of free electron per atom means total free electrons total number of atoms Mw Number of free charge particle per unit volume n NAXM M N total free charge particle total volume 6 023 x 1023 x 104 6 023 x 1028 10 d

In the circuit shown ratio of capacitors is C C 4 3 and terminal voltage of the battery connected at the left end is V If the terminal voltage of the battery connected at the right most end is in such a way that the potentials of nodes 1 2 3 4 5 and 6 are in a geometric progression of forms Vox then the value of x y is Note x y are integers V C 3 C C C 5 4 100000 CT TT C T C

3 Two identical conducting spheres are charged induction and then separated by a large distance sphere has charge Q and sphere 2 has charge Q A third sphe is initially uncharged If sphere 3 is touched to sphere and separated and then touched to sphere 2 and separate what is the final charge on each of the three sphoron

0 Two coils are placed close to each other The mutual inductance of the pair of coil depends upon 1 The current in the two coil 2 The rate at which the current are changing in two coil 3 Relative position and orientation of the coil 4 The material of wires of the coil

A liquid vessel containing liquid moves down a smooth incline plane of angle of inclination 30 Find the angle p made by free surface of liquid with the horizontal plane L Question Type Single Correct Type 1 15 2 30 30 3 45

All India Aakash Test Series for NEET 2021 24 To is time period of oscillation of the needle in uniform horizontal magnetic field BH of earth If another magnetic field is applied perpendicular to BH such that the needle deflects by 0 for its equilibrium Now period of oscillation of needle is T The relation between T and To is 1 T T2 cos 0 2 T T cose To T 3 T 2

In the figure shown the lens has a focal length 40 cm The optical axis of the lens is the x axis and it is fixed at x 60 cm A point object O is placed at the origin of coordinates The center of the flat mirror is at x 150 cm while the angle 8 shown is increased from 30 to 60 If the distance travelled in centimeters by the image formed after a refraction from the lens and reflection from the mirror during the variation of 8 is given by 5 am the value of a is O X O THOMFRULL m

Two sound waves of slightly different frequencies have amplitude ratio What is the difference of sound levels in decibels of maximum and minimum intensities heard at a point Question Type Single Correct Type 1 100 2 10

d indepen A convex lens of focal length 40 cm is held co axially 12 cm above a mirror of focal length 18 cm An object held x cm above the lens gives rise to an image coincident with it Then x is equal to a 12 cm 0 b 15 cm 18 cm Ve d 30 cm X I 120 18cm of mass 3 kg is under a constant force whic

A conducting sphere having radius R as charge Q Another point charge 2Q is placed at a distance 2R from the centre of the sphere What is the net electric potential at the surface of the sphere Question Type Single Correct Type 1 2 KQ R 3KQ R AVA

a single Silt with A 500nm lens of diameter then width of 0 1mm central maxima obtained on screen at a distance of 1m will be Conside diffraction and a lens a Question Type Single Correct Type 15 mm 2 1 mm 3 10 mm 4 2 5 mm

Free fall of an object in vacum near the surface of earth is motion with 1 uniform velocity 2 uniform acceleration 3 variable acceleration 4 constant momentum

d 6 320 J e 6 032 N m t 0 0006032 m 11 The length breadth and thickness of a rectangular sheet of metal are 4 234 m 1 005 m and 2 01 cm respectively Give the area and volume of the sheet to correct significant figures bor measured by a grocer s balance is 2 300 kg Two gold pieces of What is a the total mass of the

When the particle completes half of the revolution along a circular path with constant speed The work done by the centripetal force is 1 Zero 2 my 2 3 mv 4 my r

4 100 A space ship of mass Mmoves in the absence of external forces with a constant velocity vo To change the motion direction a jet engine is switched on It starts ejecting a gas jet with velocity u which is constant relative to the spaceship and directed at right angles to the spaceship motion The engine is shut down when the mass of the spaceship decreases to m Through what angle a did the motion direction of the spaceship deviate due to the jet engine operation m C

4 93 Three identical discs A B and C rest on a smooth horizontal plane as shown in figure 4 151 The disc A is set in motion with velocity v along the perpendicular bisector of the line BC joining the centres of the stationary discs The distance BC between the centres of stationary discs B and C is n times the diameter of each disc At what value of n will the disc A recoil Stop and move on after elastic collision Figure 4 151 Ans n 2 n 2 n 21 B I 1 1 1 1 nd C

For a substance the average life for a emission is 3240 years and for emission is 810 years After how much time the 1 4 of the material remains by simultaneous emission ln2 0 693 648 years O 324 years O 449 years 898 years

A particle moves according to the equation x 12t where x is in meters and it is in seconds a Find the average velocity for the time interval from 1 95 s to 2 95 s m s b Find the average velocity for the time interval from 1 95 s to 2 25 s

table in the s A ched what the ng al en of mas A spool m sts on a rough horizontal surface as shown in figure 5 148 Its moment of inertia relative to its own axis is equal to I ymR2 where y is a numerical factor and R is the outside radius of the spool The radius of the wound thread layer is equal to r The spool is pulled without sliding by the thread with a constant force F directed at an angle 0 to the horizontal Find a The projection of the acceleration vector of the spool on the X axis and b the work performed by the force F during the first t seconds after the beginning of motion R Figure 5 148 2 8 1 F cose 12 p r cos0 17 F 2 Ans R R F Ka a X 10

1 104 A particle moving in the positive x direction has initial velocity vo The particle undergoes retardation kv where v is its instantaneous velocity The velocity of the particle as a function of time is given by A v v 1 kvot C v Vo kt B v D v D 210 1 kt Vo 2 2 1 k vot

A plane mirror is moving with velocity e 41 53 8k The point object in front of the mirror hen add 3 im each case moves with a velocity 31 41 5k Here k is along the normal to the plane mirror and facing towards the object The velocity of the images is 1 31 41 5k 2 31 4j 11k 31 31 4 11k 4 7i 41 11k Ans 2

A galvanometer coil oscillates with a periodic time of 5 second and successive maximum displacements are observed at 76 0 34 2 15 5 and 6 9 scale divisions Compute a Logarithmic decrement b Damping factor c Deflection of the galvanometer coil in the absence of damping

56 A platform of mass m and counter weight of M m Where M 3m are connected by a light cord which passes over two smooth pulleys A man of mass M is standing on the platform which is at rest If the man leaps vertically upwards and out of platform with velocity 10ms find the distance through which the platform will descend B 2m A 1m C 3m D 4m

having inclination angle atan 1 5 of mass m is lying on a weder Wedge is moving with a constant 25 acceleration a m s The minimum value of coefficient of friction p so that me remains stationary w r t to wedge in g 10 m s A vork m A B 5 12 a 25 m s C 3 5 D

3 The frequency of vibration f of a mass m suspended from a spring of spring constant k is given by a relation f cm ky where c is a dimensionless quantity The value of x and y are 1 2 2 1 X 1 3 x 2 X 2 12 x 2 X 11 4 X V I 1 2 1 2

Current through a resistance R varies with time t as I t lo 1 0 t to If total charge flown s through resistance in time interval t 0 to t to is Qo then heat dissipated in resistance R in this time interval is Find the value of n n Q R n 1 to

A 10 metric ton truck drives up a hilly road of gradient 1 in 50 at a speed of 36 km h 1 If the coefficient of kinetic friction between the road and tyres is 0 2 find the power delivered by the engine g 10 m s 1 12 104 W 3 22 x 104 W 2 32 104 W 4 2 2 x 104 W

An AC circuit contains only inductor and capacitor joined to a source with e m f given as e 4 2 sin wt V Inductive reactance and capacitive reactance are different Calculate e in volt at instant when instantaneous power delivered by source is maximum Correct answer 04

When I am rest that means I am in inertial frame of reference when a train is coming velocity or accleration both case is train in non inertial frame of reference respect to me According to Newton law s of motion

Two blocks of masses M and 2M are connected to a light spring of spring constant K that has one end fixed as shown in figure The horizontal surface and the pulley are frictionless The blocks are released from rest when the spring is non deformed The string is light I Maximum extension in the spring is 4 Mg K II Maximum kinetic energy of the system is III Maximum extension in the spring is 2M g K 2 Mg K IV Maximum kinetic energy of the system is Then which of the following option is correct 4M g K 000000 M 2M

A small block of mass m is attached at the bottom end of an elastic massless rod of length L area A and Young s modulus Y Elastic energy stored in the rod is 1 3 mg L AY 2 mg 2 L AY 2 mg L 2AY 4 Zero

10th step A ball rolls horizontally off a stair case with initial velocity u and just manages to hit the 10th step as shown If length of each step is 20cm and height is 10 cm initial speed of the ball is g 10 m s 1 2 5 m s 2 3 2 m s 3 2 3 m s 4 5 2 m s