Physics Questions

Two blocks A and B are separated by some distance and tied by a string as shown in the figure The force of friction in both the blocks at t 2 sec is A 4 N 5 N C ON 10 N F 21 m 1 kg H41 0 6 B 2 N 5 N D 1 N 5 N m 2kg H 0 5 F 5N

A rectangle is inscribed in the parabola y x 3 as shown with its base on the x axis L 3 A x 2 4F Write the area A of the rectangle as a function of x A x 19 X Open A x 1 x y 4H y 2 Find the domain of the function Enter your answer using interval notation 0 00 x Tutorial 2 Find the objective function for the given calculus problem Give the domain of the objective function but do not actually attempt to solve the problem Domain Enter your answer using interval notation X 1 An open rectangular box is to be constructed with a square base and a volume of 96 000 cm See the figure below cm 2 3 a Find the dimensions of the open box that require the least amount of material Let A represent the surface area of the open box Enter your answer in terms of x 384000 X cm X b If the rectangular box in part a is closed find the dimensions that require the least amount of material Let A represent the surface area of the closed box terms of x 2x 384000 1 UN DEF 0 0 DINE

are placed on top of each other on a horizontal table If the mass of each coin is 10 g and acceleration due to gravity is 10 ms 2 what is the magnitude and direction of the force on the 7th coin counted from the bottom due to all the coins above it 1 0 3 N downwards 3 0 7 N downwards 2 0 3 N upwards 4 0 7 N upwards

Two blocks of mass 2kg 3kg respectively are placed on rough inclined having inclination angle 0 37 as shown in the diagram N is the normal reaction between the two blocks 37 2kg 3kg H If H H 0 5 a a 0 N 0 If H H 0 5 a a2 0 N 0 2

Two force are acting on a particle as shown in the figure A third force is applied on the particle such that net force on the particle becomes along positive x axis What is the magnitude of third force in newton y 10 N 53 12 N X

A man drags a box with uniform speed across a 10 m rough floor The coefficient of friction of the floor is 0 5 If the man pulls the box with a force of 3 kN at an angle 30 with the horizontal what is the work done in dragging the box A 30 kJ 15 C kJ B 15 kJ D 5 Kj

A body of mass 0 5 kg is placed on ground The coefficient of friction between the mass and the ground is us 0 2 A horizontal force F 2 sin t is applied on the mass as shown in the figure Find the 77 velocity of the body when its acceleration becomes zero for the first time after start Take g 10 m s A 0 C 2 73 m s B 3 6 m s D none of these

The spectral emissive power Ex for a body at temperature T is plotted against the wavelength and area under the curve is found to be A At a different temperature T the area is 2 found to be 9A Then dE d 2 is T T

A 1 5 kg block is initially at rest on a horizontal frictionless surface when a horizontal force in the positive direction of x axis is applied to the block The force is given byF 4 x N where x is in metre and the initial position of the block is x 0 The maximum kinetic energy of the block between x 0 and x 2 0 m is A 2 33 J C 5 33 J B 6 87 J D 6 67 J

A monkey B shown in figure is holding on to the tail of monkey A who is climbing up a rope The masses of the monkey A and B are 5 kg and 2 kg respectively If A can tolerate a tension of 30 N in its tail what force should it apply on rope to carry the monkey B with it A 70 N C Between 70 and 105 N B 105 N D cannot say

3 45 4 60 Three blocks of masses 4 kg 2 kg and I ke ram nee respectively are in contact on a frictionless table as shown in the figure If a force of 14 N is applied on the 4 kg block the contact force between the 4 kg and the 2 kg block will be 14 N 1 2 N 721 ON 4 kg 2 kg 1 kg 2 6 N 14N

A thin bar magnet is placed in a uniform magnetic field and is aligned with the field The needle is now rotated by an angle of 45 and the work done is W The torque on the magnetic needle at this position is 1 zero W 5 2 3 W 2 4 zw

Power supplied to a particle of mass 2 kg varies with time as P 3t watt Here t is time in 2 second If velocity of particle at t 0 is v 0 the velocity of particle at time t 2 s will be A 1 m s C 2 m s B 4 m s D 2 2 m s

Three blocks are placed at rest on a smooth inclined plane with force acting on m parallel to the inclined plane Find the contact force between m and m F 1 10 m m2 m m m F m m3 2 m F m m m

A 10 kg block is pulled along a frictionless surface in the form of an arc of a circle of radius 10 m The applied force F is 200 N as shown in figure If the block started from rest at P then A the velocity at Q would be 20 m s B the velocity at Q would be 27 m s C work done by gravity is negative D work done by gravity is positive

man of mass 50 kg stands on a frame of mass 30 kg He pulls on a light rope which passes over a pulley The other end of the rope is attached to the frame For the system to be in equilibrium what force man must exert on the rope g 10m s 1 100 N 3 300 N 2 400 N 4 500 N

Two blocks A and B of same mass are connected through a string and arranged as shown in figure When the system is released from rest and there is no friction then A acceleration of A is g 2 B acceleration of A is g 4 C tension in the string is zero D tension in the string is mg 4 my 30 whyl 1

The pulleys and strings shown in the figure are smooth and of negligible mass For the system to remain in equilibrium the angle a should be m 1 0 3 45 2 2m 2 30 4 60 m

If the speed v of a particle of mass m as function of time t is given by v A sin where A has dimension of 5 m length A the argument of trigonometric function must be a dimensionless quantity B Dimensional formula of oo is LT C Dimensional formula of k is MLT 2 D Dimensional formula of k m is T

A block of mass 10 kg is suspended by three strings as shown in the figure The tension T is 100 N 3 3 100N questionper 60 T T 10 kg 30 T 100 2 N 4 50 3 N

An inductor of inductance 20 mH is connected across the terminals of a capacitor of capacitance 2 F which is initially charged to a potential 10 2v The charge on the capacitor when the energy stored in the capacitor becomes equal to the energy stored in the inductor is O 20 C O 10 C O 5 C O 25 C

4 57 Figure 4 115 shows a boy on a horizontal platform A on a smooth horizontal surface holding a rope attached to a box B Boy pulls the rope with a constant force of 50 N The combined mass of platform A and boy is 250 kg and that of box B is 500 kg The velocity of A relative to the box B 5 s after the boy on A begins to pull the rope will be TA A 1 m s C 2 m s goodley AE Figure 4 115 B B 1 5 m s D 0 5 m s orig 30 A C 4 0 ba ORE he de ce th

A block of mass 2 kg is placed on rough horizontal surface and pulled with a horizontal constant force F that its velocity remains 2 cm s constant If coefficient of friction between surface and block is 0 2 then value of work done in J by F in 10 sec is

When 100 V DC is applied across a solenoid a current of 1 A flows in it When 100 V AC is applied across the same coil the current drops to 0 5 A If the frequency of the AC source is 50 Hz the impedance and inductance of the inductor for the given AC circuit are O200 Q and 0 55 henry O 100 Q and 0 86 henry O 100 Q and 1 0 henry 100 Q and 0 93 henry

A cylinder with radius R spins about its horizontal axis with angular speed w There is a small block lying on the inner surface of the cylinder The coefficient of friction between the block and the cylinder is u Find the possible values of w for which the block remains at rest with respect to the cylinder Take R 1 m 0 2 AR 0

Example 3 1 a Estimate the average drift speed of conduction electrons in a copper wire of cross sectional area 1 0 x 107 m carrying a current of 1 5 A Assume that each copper atom contributes roughly one conduction electron The density of copper is 9 0 x 10 kg m and its atomic mass is 63 5 u b Compare the drift speed ob Ined above with 1 thermal speeds of copper atoms at or inary temperatures ii speed of propagation of electric field along the conductor which causes the drift motion Solution a The direction of drift velocity of conduction electrons is opposite to the electric field direction i e electrons drift in the direction of increasing potential The drift speed v is given by Eq 3 18 V I neA Va Now e 1 6 x 10 19 C A 1 0 x 107m I 1 5 A The density of conduction electrons n is equal to the number of atoms per cubic metre assuming one conduction electron per Cu atom as is reasonable from its valence electron count of one A cubic metre of copper has a mass of 9 0 x 10 kg Since 6 0 x 1023 copper atoms have a mass of 63 5 g 6 0 x 1023 63 5 8 5 x 1028 m n which gives V x9 0 106 1 5 85x1028 x 16 x 10 19 V 010 7

nswer given a 5 Bottom arm of a U tube of uniform section has length I and the vertica arms have length 31 each The tube is held with its parallel arms vertica and filled with a liquid of density p to occupy a total length of 4l of the tube and then it is made to accelerate horizontally in the plane of the tube with an acceleration g that is modulus of acceleration of free fall What will gauge pressure at the midpoint of the bottom arm b immediately after acceleration of the tube is made abruptly zero a pgl c 50gl b 2 pgl d 1 375 ogl

Figure shows a man of mass m holding a ladder attached to a weight of mass M by a string supported by a light smooth pulley If whole system is at rest initially and man climbs up the ladder by a distance relative to ladder then the displacemen ml of centre of mass system is xM Find the value of x www m HOKI M

A particle starts from rest from point P and follow a path PQ on the three surfaces as shown in figures If time taken by the particles in three cases are t t and 13 then select INCORRECT statement Ot3t t1 Oa a2a3 O t 1 13 O V1 V2 V3 AAA h 45 Case I Q Case II Q h 60 P h 30 Case III Q Marks 4 1

11 A potentiometer consists of a wire of length 4 m and resistance 20 S2 If it is connected to a cell of emf 20 volt the potential difference per unit length of the wire will be b 2 Vm 1 a 0 5 V m 1 c 5 Vm 1 d 1 0 V m 1

7 State whether the following statements are true or false If zero of the potential energy is not at infinity even then total energy of an orbiting satellite is negative of its kinetic energy The force of attraction between a hollow spherical shell of uniform density and a point mass placed outside it is zero i The force of gravity is a conservative force O True True False True True True O False True True False False True

The friction of the air causes a vertical retardation equal to 10 of the acceleration due to gravity Take acceleration 10m s The maximum height and time to reach the maximum height will be decreased by

Consider a plane electromagnetic wave propagating in free space and having an electric field distribution given by 3 2 4 0 1 0 1 E E ax ay 2 2 where E and a are constants Calculate the corresponding magnetic field R

The series combination of two batteries both of the same emf 10 V but different internal resistance of 20 2 and 5 2 is connected to the parallel combination of two resistors 30 22 and R 22 The voltage difference across the battery of internal resistance 20 2 is zero the value of R in 2 is Main 8 Jan 2020 II

A Daniel cell is connected to the primary coil of a transformer If the output voltage of the Daniel cell is 10 V and the ratio of secondary to primary coil turns of transformer is 2 then the voltage in the secondary will be 05V O 10 V O 20 V O Zero

The magnetic flux linked with a circuit of resistance 10 ohm increases from 20 Wb to 52 Wb in 50 s The magnitude of charge flown through the circuit will be equivalent to O 2x 1019 protons O 10 protons O 6 x 108 protons O 8 x 103 protons

Electromagnetic waves travel in a medium which has relative permeability 1 3 and relative permittivity 2 14 Speed of electromagnetic waves in this medium will be O 13 60 x 106 m s O 1 8 x 106 m s O 3 6 x 108 m s O 1 8 x 108 m s

A particle is moving with constant speed u inside a fixed smooth hemispherical bowl of radius a describes a horizontal circle at a distance below its centre Then a The radius of the circular motion is 2 The value of u is ag 2 3 3a 2 The normal reaction of the spherical surface on mg the particle is 2 The magnitude of the resultant force acting on

fourth option without selecting any incorrect option second option in this case will result in 1 marks A ball lies on a carpet Carpet is kept on smooth horizontal floor Carpet is pulled as shown in figure There is no slipping between ball carpet ball Carpet pull Acceleration of center of mass of ball is in the direction of acceleration of carpet Acceleration of center of mass of ball is in opposite direction of acceleration of carpet O Direction of angular acceleration of ball is out of the plane of paper Work done by friction on ball carpet system is non zero

A disc of mass M radius R moves under gravity while unwinding string under non slip condition Mark the correct statement s AY M X Acceleration of the centre of the disc is in direction 0 Rate of change of angular momentum L of disc d about a point along string is in k direction dt Angular momentum of disc is conserved about centre of mass Rate of change of angular momentum dL of disc about center of mass is in direction dt

The electric field intensity produced by the radiations coming from a 100 W bulb at a 6 m distance is E The electric field intensity produced by the radiations coming from 25 W bulb at the 3 m distance is O2E O 3E OE OE

along a straight line is as shown in the figure At what time the particle acquires its initial velocity a m s 10 1 12 s 2 5 s 4 3 8 s t s 4 16 s

For a cell a graph is plotted between the potential difference V across the terminals of the cell and the current drawn from the cell The emf and internal resistance of the cell are V volt 4 3 2 1 of 0 1 2 V and 22 3 2 V and 42 I A 2 4 V and 22 4 4 V and 49 N

Fig 2 2 shows the same measuring cylinder after stone A has been lowered into it on a fine tring f 12 Fig 2 1 44 2 cm water Calculate the volume of stone A Fig 2 2 60 4 cm volume b The mass of stone A is measured as 40 5g Calculate the density of the rock from which stone A was formed cm 2

A particle is projected from a tower of height H with a speed of 50 m s at an angle of 37 with the horizontal Then select the CORRECT alternative s take point of projection as origin 0 0 3 Equation of trajectory of particle is y x x 320 25 Particle moves perpendicular to initial direction at 3 sec O Minimum speed of particle in subsequent motion is zero Maximum height attained by the particle from the point of projection is 45 m

80 A 500 H inductor pF capacitor and a 6280 resistor are connected t form a series LCR circuit Calculate the resonant frequency and Q facto of this circuit at resonance O fr 2500 kHz Q 10 O fr 2500 kHz Q 12 5 Ofr 3000 kHz Q 10 O fr 3000 kHz Q 12 5

A thin bar magnet when placed in a magnetic field of magnitude 2 T performs 10 oscillations per second The magnet is now divided into three equal parts by cutting perpendicular to its axis and kept in a magnetic field of magnitude 4 T Now each part would oscillate with a frequency of O 40 Hz O16 Hz o 302 HI 0 23 Hz

A block of mass 10 kg is at rest on rough inclined of inclination 37 with help of a constant force F Force F have magnitude 20 N At t 0 another force F2 start acting on block Magnitude of force F changes with time as F 10t N Both forces F and F are parallel to inclined and are acting up the inclined Friction force acting on block is f Match the list I and List II Coefficient of friction between block and inclined is 0 5 List l t 4 sec 11 t 7 sec t 10 sec IV t 15 sec List ll P f 0 Q f 30 N R f 40 N S f 60 N T f 80 N 10kg 37 F 20N F 10t

A uniform chain of length I is placed on a smooth horizontal table such that half of its length hangsover one edge It is released from rest the velocity with which it leaves the table is A 3gl B C 3gl 2gl V 3

24 A liquid flows out drop by drop from a vessel through a vertical tube with an internal diameter of 2 mm then the total number of drops that flows out during 10 grams of the liquid flow out Assume that the diameter of the neck of a drop at the moment it breaks away is equal to the internal diameter of tube and surface tension is 0 02 N m