Physics Questions

Three parallel bolting forces act on the rim of the circular cover plate as shown in Fig 3 b Determine the magnitude nature and point of application of the resultant force with respect to origin O 6 200 N B 300 N A 0 Z 150 N 450 0 8 m C

c 35 x 10 7 N towards wire d 35 x 10 7 N away from wire Two conducting circular loops of radii R and R R R are placed in the same plane with their centres coinciding The mutual inductance between them will be directly proportional to a R R b c R R A R d R R

I PROBLEM SOLVING Solve the problems below using the step by step procedure that was previously taught in this module 4 points 7 10 Calculate the energy required to increase the temperature of 20g of water from 2000 to 100 OC Given Formula Solution Answer

1 i Two coils A of 12 500 turns and B of 16 000 turns lie in parallel planes so that 60 of flux produced in A links coil B It is found that a current of 5A in A produces a flux of 0 6 mWb while the same current in B produces 0 8 mWb Determine i mutual inductance and ii coupling coefficient

An assembly placed on a frictionless floor consists of two light bars A and B four light springs and a block C of mass m Stiffness of each springs is shown in the figure Initially all the springs are relaxed and the bars are parallel to each other The bar A is pulled from its midpoint towards the right by a force that increases gradually from zero When the block acquires an acceleration a by what amount will the separation between the bars increase k ENGEDHETENDE FAR ALPERESENTES k B C SENDESENTO A Pull

4 Same at all positions of earth In Delhi and Mumbai magnetic needle shows 21 facta the true north quite accurately because 1 In Delhi and Mumbai angle of dip is small 2 In Delhi and Mumbai angle of dip is large 3 In Delhi and Mumbai angle of declination is small 4 In Delhi and Mumbai angle of declination is large TETE 4 1 face 2 face au 3 face 4 face f f EE

A stretching force of 10N is applied at one end of a spring balance and an equal stretching force is applied at the other end at the same time What will be the reading of the balance 1 5N 2 10N 3 3 20N 20N 4 0

29 The earth s magnetic field at the equator is 29 gada a total approximately 0 4 G Then the earth s dipole at year an faya moment will be 1 1 05 x 1023 A m 3 9 5 x 1023 A m 2 5 05 x 1023 A m 4 1 05 x 1021 A m 1 1 05 1023 A m 2 x 3 9 5 x 1023 A m 4

20 Refrigerator is to maintain eatables kept inside at 7 C If the room temperature is 43 C coefficient of performance of refrigerator must be NCERT Pg 322 1 7 78 2 13 7 3 9 72 4 0 75

A force acting on a particle A must change the direction of motion of the particle B must change the magnitude of velocity of the p C must change the momentum of particle D must have its reaction on the particle

In a bicycle speedometer a attached to the spokes of the wheel and a coil is attached to the frame so that the north pole of the magnet moves past it once for every revolution of the wheel As the magnet moves past the coil a pulse of current is induced in the coil A computer then measures the time between pulses and computes the bicycle s speed Figure shows the magnet about to move past the coil Which of the graphs shows the resulting current pulse Take counterclockwise in figure current to be positive Magnet north pole facing the viewer Plane of Coil is nearer to you 1 v A A N 4 3 2

5 Find the net deviation produced in the incident ray for the optical instrument shown in figure Take refractive index of the prism material as 2 1 66 CW 2 66 ACW 3 54 ACW 4 54 CW 30 6

2 2 Three point masses each of mass m rotate in a circle of radius r with constant angular velocity due to their mutual gravitational attraction If at any instant the masses are on the vertex of an equilateral triangle of side a then the value of wis a CR c V Gm 3 a Gm 3 3a ei noass b 3Gm 3 a d None of these

A proton and an electron are held apart a distance of 1 m and then let go Where would they meet O E P a in the middle b closer to the electron s side c closer to the proton s side

The ionization energy of the electron in the hydrogen atom in its ground state is 13 6 eV The atoms are excited to higher energy levels to emit radiations of 6 wavelengths Maximum wavelength of emitted radiation corresponds to the transition between a n 3 to n 1 states b n 2 to n 1 states c n 4 to n 3 states d n 3 to n 2 states

nce will increase 33 What is the net force on the rectangular coil a b B 2A 1A 2 cm A 25 x 10 7N towards wire 25 10 N away from wire x 35 x 10 7 N towards wire 10 cm c 15 cm c d 35 x 10 7N away from wire 34 Two conducting circular loops of radii R and R R R are placed in the same p with their centres coinciding The mutual inductance between them will be dire

9 A force F acts between two charges Q and Q that is placed at a certain distance from eac other The third sphere of charge Q is placed between them What is the magnitude and force experienced by the third charge A 3F in the direction of Q charge B 4F in the direction of Q charge C 8F in the direction of Q charge D No direction and magnitude is zero

27 4 A B C D Which planets have maximum minimum magnetic fields respectively 1 Jupiter Venus 2 Mercury Mars 3 Jupiter Mars 4 Venus Mercury A solenoid has core of material with relativo 27 3 A C 1 2 3 4 4 A B C D

X 9 m 1 1 2 m Negre interaction changes Find Vo ve particles do not t each other b w th if v 28 2 final L

A conducting bar of length L is free to slide on two parallel conducting rails as shown in the figure R Two resistors R and R are connected across the ends of the rails There is a uniform magnetic field B pointing into the page An external agent pulls the bar to the left at a constant speed V R The correct statement about the directions of induced currents I and I2 flowing through R and R respectively is A Both I and 12 are in clockwise direction B I is in clockwise direction and I2 is in anticlockwise direction I is in anticlockwise direction and I is

A point charge 2Q is placed at a distance of 8 cm from centre of a disc on the axis of disc having radius R 6 cm Total electric flux passing through this disc is 2Q 8 cm 10 Q 280 Q 480 R 6 cm

If current is doubled the deflection is also 14 f doubled in aga 1 Tangent galvanometer 2 Moving coil galvanometer 3 both 1 and 2 4 None of above 1 2 3 1 72 4

For the circuit shown the switch was at a for long time At t 0 the switch is moved to b The solution for the capacitor current variation found to be i t 2 5 e 0 5 mA for 120 Find the values of V 2 and R 5V t 0 1kQ2 www 1mF i R www V 2

3 You are at the airport A moving sidewalk moves East at 2 5m s with a supermodel just standing on it letting the sidewalk move her As you sit on a bench people watching you observe a dad pushing a child in a stroller walking parallel to the moving sidewalk 1 0m s west A hurried professional is traveling at 5 0m s E total while on the moving sidewalk and has to avoid the 9 year old child walking west at 2 5m s on the floor and headed toward the moving sidewalk What is the velocity of the dad relative to the professional What is the velocity of the supermodel relative to the professional C What is the velocity of the professional as soon as they leave the sidewalk d What is the velocity of the 9 year old relative to you when the 9 year old steps onto the moving sidewalk a b

8 In the circuit shown the capacitor initially had a charge 5 C as shown in the figure The switch is closed at time t 0 Find i the initial current through the resistor ii the net heat dissipated after a long time iii the charge across the capacitor plates in time t 10V 1pF 5pc

Mass M is divided into two parts m and m For a given separation the ratio of for which the m M gravitational attraction between the two parts becomes maximum is 1 1 1 3 1 3 2 1 2 4 1 4

A Polychromatic Beam passing through Hydrogen Gas A beam of ultraviolet radiation having wavelength 1000A to 2000A is incident on a sample of atomic hydrogen gas Assuming that all atoms of gas are in ground state which wavelengths will have low intensity in the transmitted beam

wo poin the circumference of a uniform conducting ring of radius r and resistance R Arc AB of the ring subtends an angle 0 at the centre The value of the magnetic induction at the centre due to the current in the ring is Resita R R 360 6 21 20 215 P A 1 zero only if 0 180 2 zero for all values of 0 3 proportional to 2 180 0 B 36 1 362 BE

A block of mass m is placed on a smooth inclined plane of inclination 0 with the horizontal The force exerted by the plane on the block has a magnitude A mg B mg cose C mg cost D mg tane

11 In a non ohmic conductor electron density varies with electric field as n x E Find how the current varies with applied voltage for this conductor if drift velocity is proprotional to the applied electric field GOIITJEE SALT LAKE 98741956751 BALLYGUNGE GOLPARK 7044094543 goiitjee gmail com I www iitopper com

0 For a simple harmonic oscillator of mass 10 kg and amplitude A 2m the variation of potential energy U as a function of displacement x from mean position is as shown The time period of oscillation in seconds is UA 1 2 2 4 3 T AY 2 T 2m 30 J TO J 0 2m X

Total amount of work done in establishing the 5 current I in coil of inductance L is 1 W I dl 1 ar 1 41 3 W 2 W LI dl 4 W LI dl L fant 1 3

Q6 Assertion The emergent ray is parallel to the direction of the incident ray Reason The extent of bending of the ray of light at the opposite parallel faces air glass interface and glass air interface of the rectangular glass slab is equal and opposite

Three vessels placed on horizontal ground are shown in figure All three vessels are symmetric about the dotted line shown Which of the following are correct 11 C A B A if all the three vessels are filled with water upto dotted line then they pressure is same on the bottom surface B if all the three vessels are filled with equal volumes below dotted line with water and if base areas are same then equal pressure on the bottom surface C if all three vessels but below dotted line of same base area are filled with equal masses of three different liquids PA PB Pc on container due to liquid is same D in option C force on the base of vessel A is maximum

5 1 Three particles each of mass m are located at the vertices of an equilateral triangle of side a At what speed must they move if they all revolve under the influence of their gravitational force of attraction in a circular orbit a Va 2Gm circumscribing the triangle while still preserving the equilateral triangle 0102691 1922A Gm b c ch of mass m rotate in a circle due to a 3Gm m a Am d 4Gm B a m

Three thin wires of equal length are suspended from the top of a roof The respective ratio of their area of cross section is 1 2 4 and Young s modulii is 4 2 1 then the ratio of their weights to be attached at the other ends to obtain same elongation in them is

A parallel plate air core capacitor is connected across a source of constant potential difference When a dielectric plate is introduced between the two plates then A some charge from the capacitor will flow back into the source ce some extra charge from the source will flow into the capacitor C the electric field intensity between the two plates does not change D the electric field intensity between the two plates will decrease

Convection 3 Conduction 4 Temperature remains same 36 A liquid cools down from 70 C to 60 C in 5 minutes The time taken to cool it from 60 C to 50 C will 1 5 minutes 2 Lesser than 5 minutes 3 Greater than 5 minutes Lesser or greater than 5 minutes depending upon the density of the liquid

Magnetic field at a distance d from a short bar 3 magnet in tan A and tan B position are in ratio 1 2 1 exact 2 2 1 approx 3 1 2 exact 4 1 2 approx 7 1 2 1 ho 2 2 1 TT 3 1 2 4 1 2 S

Pls explain this with theory 96 The capacitor of capacitance C in the circuit shown is fully charged initially resistance is R After the switch S is closed the time taken to reduce the stored energy in the capacitor to half its initial value is S30 a RC 2 C c 2RCIn2 wwww d R b RCIn2 RCIn2 2 KVPY 2012

evel E M T Quality TA A body of mass 10 kg and velocity 10 m s collides with a stationary body of mass 5 kg After collision both bodies stick to each other The common velocity would be A 3 20 ms 1 B 20 3 ms 1 C 10 3 ms 1 D 3 10 ms 1

Charge Q coulomb s is uniformly distributed throughout the volume of a solid non conducting hemisphere of radius R then potential at its centre is 1 2 3 fo 1 Q 4meo 4R 1Q 41 R 1 3Q 420 2R 1 3Q

Two balls with charges Q and 4Q are separated by 3R Where should you place another charged ball Q on the line between the two charges such that the net force on Q will be zero e Od 9 b R 3R d 2R 4Q

If the angular speed of earth increases to n n times the present value then acceleration due gravity at poles 1 Increases to n2 times 2 Decreases to n times 3 Decreases to n times

7 A person says that he measured the acceleration of a particle to be nonzero while no force was acting on the particle A He is a liar B His clock might have run slow C His meter scale might have been longer than the standard D He might have used noninertial frame

An object will continue accelerating until A resultant force on it begins to decrease B its velocity changes direction C the resultant force on it is zero D the resultant force is at right angles to its direction of moti

Two particles A and B of mass 1 kg and 4 kg respectively approach each other due to their mutual gravitational force only Then the ratio of acceleration of A to B at any instant is 1 4 1 V 3 1 2 2 2 1 4 1 4

questions A man of mass 60kg sitting on ice pushes a block of mass of 12kg on ice horizontally with a speed of 5 ms The coefficient of friction between the man and ice and between block and ice is 0 2 The distance between man and the block when they come to rest is g 10ms YOUR ANSWER CORRECT ANSWER IS 6 25 CYDIANATION 4 6 5

In the potential energy curve for the formation of H molecule as a function of internuclear distance of H atoms what happens at the minimum in the curve 1 Net force of attraction equals the force of repulsion 2 Most stable state of H is achieved 3 System acquires minimum energy 4 All of these

The volume of a liquid is 26 mL A stud ent measures the volume and finds it to be 26 2 mL 26 1 mL 25 9 mL and 26 5 mL in the first second third and fourth trial respectively Describe measureme nt in the form of precision and accurac y Support your answer