Physics Questions

ray comes to the first mirror reflects and hits second mirror If this ray turns back on itself after reflecting from the second mirror find the focal point of the second mirror 3 1 1 01 2 16 3 2 2 2m 6m A 1m f 3m TTTT 6m II LLL f B 2m D 6m 6

O Single Correct MCQ A bob of mass m attached to an inextensible string of length is suspended from a vertical support The bob rotates in a horizontal circle with an angular speed rad s about the vertical About the point of suspension A B C D angular momentum changes in direction but not in magnitude angular momentum changes both in direction and magnitude angular momentum is conserved angular momentum changes in magnitude but not in direction

uniform circular motion changes continuously A Angular displacement is vector quantity only for small values R The direction of angular displacement is perpendicular to plane of rotation of object

A glass prism of refractive index 1 5 is immersed in 4 a liquid of refractive index as shown in the figure 3 A light beam incident normally on the face PQ is totally reflected to reach the face QR if 1 sin 0 8 9 1 5 4 3 2 sin0 8 9

The 11 A large number of identical point masses m are placed along x axis at x 0 1 2 4 magnitude of gravitational force on mass at origin x 0 will be Y mm m x 0 x 1 x 2 1 Gm 3 2 Gm m x 4 and so on 2 Gm 5Gm E

Current passing through a b will be respectively 10V 1 2 3 Question Type Single Correct Type 100 1A 1A 0 0 1092 1A 0 b 100 10V

Figure shows the elliptical path of a planet about the sun The two shaded parts have equal area If t and t are the time taken by the planet to go from a to b and from c to d respectively then C S b a

The I V characteristics for two semiconductor devices are shown in figure A V Volt A a The corresponding devices are LED Solar cell LED Photodiode Photodiode Solar cell Photodiode Zener diode b V

R At resonance the applied voltage is Q times voltage drop across inductance for capacitance A If a current has both ac and dc components then a dc ammeter used to measure this current will measure the average value of the total current R The scale of dc ammeter is not uniformly divided over a long distance at F 5

A particle moves under simple harmonic motion SHM in a straight line In the first s after starting from rest it travels a distance of a and in next T S it travels a distance of 2a in the same direction Then A B C D the amplitude of its motion is 4a the time period of its oscillation is 67 the amplitude of its motion is 3a the time period of its oscillation is 87

curve 128 For the following represents the total energy emitted by the perfect black body per second per unit area E over the complete wavelength range at that temperature 7 Thus area below the graph is in accordance with Symbols have usual meanings E 4 Ex T in m 1 Wien s displacement law 2 Stefan s law 3 Kirchhoff s law AY

m st e viii A train is targeted to run from Delhi to Pune at an average speed of 80 kph but due to repairs of track looses 2 hrs in the first part of the journey If then accelerates at a rate of 20 kph till the speed reaches 100 kph Its speed is now maintained till the end of the journey If the train now reaches station in time find the distance from when it started accelerating TRA0 Im

Advanced 1D and 2D Motion L 1 The acceleration of a particle varies with time as shown Assume the particle starts from rest at t 0 the displacement of the particle from t 2s to t 4s is Stage 2 10 a m b 20 3 m a c 25 m t ins d 28 m

3 0 5 3 Temperature difference between body and surroundings fall from 10 C to 5 C in 10 minutes Temperature difference between body and surroundings will fall from 5 C to 2 5 C in Use Newton s law of cooling 1 5 minutes Ta 10 minutes 2 20 minutes 4 Infinite

If 0 is instantaneous angle which joining the particle and the centre of the loop makes with the vertical as shown then identify the correct statement s related to the normal reaction N between the block and the surface A The maximum value N occurs at 0 0 5R B The minimum value of N occurs at 0 for H 2 C The value of N becomes zero at 0 for all H 5R D Minimum value of H to complete vertical circular motion is 2

ad maximum distances of a planet sun are r and R If the minimum n its trajectory is vo its maximum 2 R m moves around the sun of mass Orbit The maximum and minimum planet from the sun are r and 2 e time period of the planet is say 10 Two point masses m and 4m are separated by a distance d on a line A third point mass m is to be placed at a point on the line such that the net gravitational force on it is zero d m 4m The distance of that point from the m mass is 1 W QN O D4 D5

9 Stationary waves are formed on stretched string If the wavelength is A then the distance between two points having maximum displacement can be 2 4 4 All of these 1 3 2 3 5 2

What is the equivalent resistance between A and B 1 2 A 3 Question Type Single Correct Type www W R R 3R 2 2R R www R M wwB R R

charge q is placed outside it as shown in figure then incorrect statement is Di B conductor C q 1 Electric field at point A due to induce charges is zero 2 Electric field at point B due to the poi charge q is non zero 3 is negative 4 Electric potentials at A and B are same

na variant of the famous problem of static equilibrium of a ladder what minimum force F must be exerted on the foot of the ladder via a rope at angle to the vertical such that the normal force Ny of the floor on the ladder goes to zero Fwl 0 Nw mg F Nf

A parallel plate capacitor is made of two circular plates separated by a distance of 5 mm with a dielectric of dielectric constant 2 2 between them The electric field in the dielectric is equal to 3 104 V m 1 The charge density of the positive plate is close to A B 3x 104 Cm C 6x 104 C m 2 C 6x 10 7 Cm 2 2 C

5 A travelling wave pulse is given by 20 m then 4 x 4t 1 The pulse is travelling along negative x axis 2 The speed of pulse is 4 m s 3 The amplitude of pulse is 5 m 4 All of these y

onem Now for second order minima 0 lution a 2 Equating by 0 10 3 we obtain a 0 8 mm a 2NO MArme marmy So 2 xample 17 A beam of light of wavelength 600 nm from a distance source falls on a single slit 1 mm wide and resulting diffraction pattern is observed on a screen 2 m away What is the distance between the first dark fringes on either side of the central bright fringe 1 E

A 24 V battery is connected in series with a resistor and an inductor with R 7 0 2 and L 7 8 H respectively a Find the energy stored in the inductor when the current reaches its maximum value J b Find the energy stored in the inductor one time constant after the switch is closed J

A ball is projected at an angle of 53 with horizontal at a speed of 20 m s on a planet named Eisteinium A horizontal wind starts blowing which gives a retardation to the ball in horizontal direction It was found that ball travels in a straight line Taking acceleration due to gravity on the planet to be 4 m s the magnitude of acceleration imparted by the wind is given by a m s The value of a is backspace

An air mass at 100 relatively humidity is forced up and over a mountain range At the peak of the mountain range immediately before it starts to descend down the other side it reaches a temperature of 2 degrees Celsius Calculate the temperature of the air mass after it has descended 360 m down the other side of the mountain range L r

1 20 kgf 3 70 kgf 2 40 kgf 4 140 kgf If spinning speed of the earth is decreased then weight of the body at the poles 1 Does not change Decreases 3 Increases 2 4 May increase or decrease

O Single Correct MCQ An open glass tube is immersed in mercury in such a way that a length of 8 cm extends above the mercury level The open end of the tube is then closed and sealed and the tube is raised vertically up by additional 46 cm What will be length of the air column above mercury in the tube now Atmospheric pressure is 76 cm of Hg A B C 38 cm 6 cm 16 cm

5 Closed organ pipe having length 48 cm and diameter 5 cm is sounded in its fundamental mode The wavelength of displacement wave produced in the pipe is 1 0 99 m 3 1 98 m 2 1 92 m 4 0 495 m

A When a body moves on a curved path with increasing speed then angle between instantaneous velocity and acceleration is acute angle R When the speed is increasing its tangential acceleration is in the direction of instantaneous velocity

in series The separation between them and relative orientation is fixed and once they are connected in configuration A and then in configuration B as below mrrrrrrrrr ooooooo A morrrrrrrolllllll B If the maximum and minimum equivalent inductance reeeeeee

1 Increase by 225 3 Increase by 125 2 Decrease by 56 4 Decrease by 144 If G is universal gravitation constant and g is acceleration due to gravity then dimensions of 1 M L 3 ML 2 M L 4 M L 69 will be

If both the blocks moving with constan acceleration then extension in spring K 1000 N m 32 N 1 3 cm 3 6 cm 7 kg oooooooo03 kg 72 N 2 2 cm 4 12 cm

Z A conductor lies along the z axis in the linear region defined by 1 5 m z 1 5 m It carries a fixed current of 10 A in the 2 direction Refer the figure shown below Note that B 3 0x 10 4e 0 2x T Find the power required to move the conductor at a constant speed to x 2 m y 0 m in 5x 10 3 s Assume the motion of the conductor to be parallel along the x axis y 2 0 1 5 NA 1 B 1 5

Refer to figure 2 E1 Find a the magnitude b x an y components and c the angle with the X axis of th resultant of OA BC and DE Y 1 O 2 0 m 30 A 90 1 0 m 60 1 5 m B X

A force F k yi xj where k is a positive constant acts on a particle moving in the x y plane Starting from the origin the particle is taken along the positive X axis to the point a 0 and then parallel to the Y axis to the point a a The total work done by the force F on the particle is 1998 a 2ka b 2ka c ka d ka

O Single Correct MCQ The coercivity of a small magnet where the ferromagnet gets demagnetized is 3x 10 A m 1 The current required to be passed in a solenoid of length 10 cm and number of turns 100 so that the magnet gets demagnetized when inside the solenoid is A B 3 A 6 A

Single Correct MCQ The current voltage relation of diode is given V 1000 where the applied T I e by 1 mA voltage V is in volts and the temperature T is in kelvin If a student makes an error measuring 0 01 V while measuring the current of 5 mA at 300 K what will be the error in the value of current in mA A 0 5 mA B C 0 05 mA 0 2 mA

5 If radius of earth contracted by 0 1 its mass remaining same then weight of the body at earth s surface will increase by 1 0 1 3 0 3 2 0 2 4 Remains same

3 Melting 26 Q heat flows per second through the rod of length L and area of cross section A If it is stretched to double its length then what will be the heat flow per second keeping temperature difference same 1 2Q Q 4 3 2 2 4 Q

1 English In the circuit shown in the figure if the potential at point A is taken to be 2V the potential at point B is R www 1 2 3 4 2A R A 3V 3V 4V 5V 5V 2A www 292 6V 1 1 B www R 5A X Your Answer

A When a conducting wire loop which is inside a uniform magnetic field directed perpendicular to its plane is moving with uniform velocity an emf is induced in it R When the magnetic flux linked with a conducting wire loop changes with position then an emf is induced in the wire ing wire is rotated about its

the correct statements a Average speed of a particle in a given time is never less than the magnitude of the average velocity du dt by It is possible to have a situation in which d dt 0 c The average velocity of a particle is zero in a time interval It is possible that the instantaneous velocity is never zero in the interval but 0 d The average velocity of a particle moving on a straight line is zero in a time interval It is possible that the instantaneous velocity is never zero in the interval Infinite accelerations are not allowed

41 Two metal spheres of radii R and 2R having some charge density o are brought in contac then charge densities becomes Dim 81m 20 3 50 50 a 2 2 810 810 20 a w wia

A radioactive element X converes into another stable element Y Half life of X is 2hrs Initially only X is present After time t the ratio of atoms of X and Y is found to be 1 4 then t in hours is x 2 3 between 4 and 6 2 4 4 6

O Single Correct MCQ In a large building there are 15 bulbs of 40 W 5 bulbs of 100 W 5 fans of 80 W and 1 heater of 1 kW The voltage of the electric mains is 220 V The minimum capacity of the main fuse of the building is A B 12 A 14 A

A metallic sphere with an internal cavity weights 40gm in air and 20gm in water If the density of the material with the cavity is 2gm CC then the volume of the cavity is 1 15CC 3 25CC 2 20CC 4 30CC

Four particles each with a mass of M equidistant from each other move along a circle with a radius of R under the action of their mutual gravitational attraction The speed of each particle is A B 1 2 GM R 1 2 2 GM R 1 2 2

162 A series LCR circuit is connected to an ac voltage source When L is removed from the circuit the phase difference between current and voltage TT If instead C is removed from the circuit 3 is the phase difference is again between current 3 and voltage The power factor of the circuit is 1 zero 2 0 5 31 0 Vik

In the circuit of the figure 1 50 kV C 6 60 F R R R3 0 870 MQ With C completely uncharged switch S is suddenly closed at t 0 At t 0 what are a current i in resistor 1 b current iz in resistor 2 and c current i3 in resistor 3 At t that is after many time constants what are d i e iz and f i3 What is the potential difference V across resistor 2 at g t 0 and h t R 48 Re ww