Physics Questions

2 23 A parallel plate capacitor of plate area A and plate separation d is connected across a battery of voltage Vand after charging of capacitor battery is disconnected Now a dielectric slab of relative permittivity k is inserted between the plates to fill the complete space between the plates Find the work done by the external agent in the process of inserting the slab into capacitor AV 1 Ans

A potentiometer wire 10 m long has a resistance of 40 Q It is connected in series with a resistance box and a 2 V storage cell If the potential gradient along the wire is 0 1 mV cm then resistance unpluggen in the box is A B C 260 Q 760 Q 960 Q

Q10 A uniform pressure of 7 0x105 N m is applied to all six sides of a copper cube What is the percentage change in volume of the cube for copper B 14x100 N O A 2 4 x 10 2 O B 0 4 x 10 10 2 00

A uniform rod of mass M and length L is hinged a one end and a spring of stiffness constant 2K attached with rod as shown in the figure The arrangement is on a smooth horizontal surface Calculate the time period of oscillation for a small angular displacement M 1 2 27K mmmm 2K 2 2 M 6K

1 A distant telephone whose resistance is 300 ohm is connected to the exchange 10 miles away by a pair of telephone wires whose resistance singly is 5 ohm per mile A twig falls across the wires at a certain point producing the effect of a resistance R connected between the wires at that point Measurements made at the exchange show a resistance between the terminals of the line of 130 ohm which rises to 160 ohm when the distant telephone is disconnected How far from the exchange is the fault to be found and what is the value of

A 150W solar PV panel produces 15V and 7A when it is connected to a load under solar insolation of 700W m 2 If the panel area is 1 5m answer the following question Use the following formula P AxI Pourt IxV n Pour P a Calculate the input power to the solar panel in Watt b What is the output power in Watt c What is the efficiency at this moment d If the system is giving the full output what is the efficiency W W

91 A hydrogen atom and a Litt ion are both in the second excited state If I and I are their respective electronic angular momenta and EH and EL thei respective energies then a and E Eil Li H b and E E and EH E c and Fl IEJ

Figure shows a bar of mass m moving with a constant speed vo on horizontal surface around a semi circular fence of radius R The average normal force acting on the bar due to contact with the fence is given by a Fill the value of a Consider all surfaces to be smooth R

I have seen the solution of this question but I did not und erstand how and why have we used the concept of TIR her e How do we know that the angle is more than the critica angle and the angle of refraction is 90 6 A fish looking up through the water sees that the outside world is contained in a circular horizon if the refractive index of water is of the circle in centimeter is and the fish is 12 cm below the surface of water the radius

conducting rod of length 5 m slides in a vertical plane against two insulated perpendicular surfaces s shown Outward uniform magnetic field B 3 tesla exists in the region If end A of the rod is being ulled with constant speed V 2 m s 7 then find the magnitude of induced Emf in volt across end A nd B of the rod at the instant when the rod makes an angle of 0 37 with horizontal B 3 T B 1 37 A 2 m s I

In Young s double slit experiment two wavelengths of light are used simultaneously where 2 22 In the fringe pattern observed on the screen 26 Fi 1 maxima of wavelength 2 can coincide with minima of wavelength 2 2 fringe width of 2 will be double that of fringe width of and nth order maxima of 2 will coincide with 2nd order maxima of 2 3 nth order minima of 2 will coincide with 2nth order minima of 2 4 none of these

5 The binding energy of an electron in the ground state of He is equal to 24 6 eV The energy required rease have emblrin definitions to remove both the electrons is a 49 2 eV erenc bin G c 79 eV The Siegram showsIonization thera e energy levels for an enerr b 54 4 eV d 108 8 eV

2 39 A parallel plate capacitor with plates kept at a separation 1cm and plate area 100cm is connected across a 24V battery Find the force with wihch one plate will attract the other plates Ans 2 5 10 N

015 sa caulap 2 0060 O A Inversely related to the frequency of the input voltage O B Directly proportional to the frequency of the input voltage O C Independent of the inductance of the inductor O D Inversely related to the inductance of the inductor

Two particles of equal masses are revolving in horizontal circular paths of radii r and r2 respectively with the same time period The ratio of their centripetal force is Question Type Single Correct Type 1 2 2

Q11 A person rubs a neutral comb through their hair and the comb becomes negatively charged Which of the following is the best explanation for this phenomenon O A The hair gains protons from the comb O B The hair gains protons from the comb while giving electrons to the comb O C The hair loses electrons to the comb D The comb loses protons to the person s hand while also gaining electrons from the hair

Two small blocks tied with a massless string of length 3 m are placed on a rotating table as shown The axis of rotation is 1 1 m from 1 2 kg mass and 2 m from 1 kg mass The angular speed w 1 rad s and the blocks do not slip Surface below 1 kg block is smooth and that below 1 2 kg block is rough friction coefficient 0 6 Choose the correct option s 1 2 kg 1 m Tension in the string is 2 N Tension in the string is 1 N 2 m 1 3 Friction force on kg block is N 1 kg

5 If a b and c then determine p and q are any three non coplanar vectors then prove that points ha mb m c 14 h a m b m c l a m b n c l a m b nac are coplanar if m m m ma 1 0 m M 13 1 1

The ammeter reading in the following circuit will be 60 www 202 wwww 602 wwww 60 www A B 1 8 LOU 2V

Four rods of same material having same cross section length have been joined as shown in figure The temperature of the junction of four rods will be 0 C 90 1 Question Type Single Correct Type 20 C 2 30 C 30 C 3 45 C 60

Relation between the ratio of specific heats y of gas and degree of freedom f will be Question Type Single Correct Type 1 y f 2 2 1 1 1 A 11 NI 3 f 2 Y 1 f 2 x 1

From the following displacement time graph find out the velocity of a moving body Time sec 30 Displacement meter Question Type Single Correct Type 1 3 m s 2 3 m s 3 3 m s

Bottom face of the glass cube is silvered as shown A ray of light is incident on to face of the cube as shown Find the deviation of the ray when it comes out of the glass cube 45 u 2 O O 0 90 O O 270 180

Six PV modules are connected in series to a load Each module has Voc 48 V and Isc 3 2 A what is the total Voc and Isc O Voc 240 V Isc 3 2A Voc 48 V Isc 3 2 A Voc 48 V Isc 16 A Voc 288 V Isc 3 2 A

Example 18 An object accelerates uniformly from initial velocity u to final velocity v It travels distance s in time t Then check the dimensional consistency of the following equations Which of them are correct physically U V 3 s ut at 2s

2 Zero 4 20 0 2 1 0 0 0 1 3 0 0 0 4 The diameter of a wire is measured to be 0 0205 x 10 m The number of significant figures in measurement is 1 Five 3 Three 2 Four 4 Nine

Q3 Two coherent beams of light having intensities I and 41 interfere to produce fringe pattem on screen The phase difference between beams is 1 2 at point A and at point B Then t difference between resultant intensifies at A and B is O A 21 8 51 O c 41 D 71

A positively charged particle moving due east enters a regi on of magnetic field directed upwards This particle will Ans move in circular path with uniform speed So won t an electric force act on it

Two fixed frictionless inclined plane making an angle 30 and 60 with the vertical are shown in the figure Two block A and B are placed on the two planes What is the relative vertical acceleration of A with respect to B

Six moles of an ideal gas perfomrs a cycle shown in figure If the temperature are TA 600 K TB 800K Tc 2200 K and TD 1200K the work done per cycle is P4 B C Question Type Single Correct Type 1 20 kJ 230 kJ T

100 g of ice at 0 C is mixed with 100 g of water at 100 C What will be the final temperature of the mixture Question Type Single Correct Type 1 10 C 2 20 C 3 30 C A 40 C

A uniform rod of length L and mass M is pivoted at the centre Its two ends are attached to two springs of equal spring constants k The springs are fixed to rigid supports as shown in the figure and the rod is free to oscillate in the horizontal plane The rod is gently pushed through a small angle 0 in one direction and released The frequency of oscillation is a c 1 12k 2TM 1 6k b d k 2TM 24k

Two men pull a rope from which a mass is hanging as shown Both apply a force of 100 N each What force should each apply to make the rope horizontal A 200 N C 600 N 230 30 B 400 N D rope cannot become horizontal

If the value of resistance is 10 845 ohm and the value of current is 3 23 amp the value of potential w significant numbers would be 1 35 0 volt BE000 2 3 50 volt nr 000

12 If electric field in a region is given as 3 k 1 1 Exi E0 E0 E 5 x 10 N C 1 2 cm then calculate the flux of electric fie passing through a rectangular plane 2 cm x 1 cr at y 2 cm N m C 1 2 Nm N m C 2 3

Q4 Ablock of transparent material is shined by a laser beam along the surface as shown in figure One half of the beam goes straight to detector while other half travels inside the block a reaches detector At detector the time delay between the arrival of two beams is 6 3 nanosecond The refractive index of the material is 1 55 1 63 O C 1 75 1 42 0 0 0 0 A B D R 3 0m Detector

A 30 kg block rests on a rough horizontal surface A force of 200 N is applied on the block The block acquires a speed of 4 m s starting from rest in 2 s What is the value of coefficient of friction Question Type Single Correct Type 1 0 33 2 0 17 3 0 47

Before jumping from the bridge Martin throws his water bottle to a friend standing on the bank of the lake The bridge is 7 0 m high The friend is standing on the bank 15 0 m from the base of the bridge with their hand 1 0 m above the ground What speed must Martin throw the bottle horizontally for it to reach his friend s hand 71 LJ

A liquid drop of diameter D is divided into 27 equal droplets If the surface tension is T then the change in energy will be Question Type Single Correct Type 1 3 D T 2 D T 3 2 D T

Which of the following measurement is more accurate 1 40 m 3 400 x 10 m 2 0 04 m 4 4 x 10 m If the random error in the arithmetic mean of 50 observations is a then the random error in the mean of 150 observations would be 1 s 2 3

Let En 2 212 8 n h be the energy of the nth level of H atom If all the H atoms are in the ground state and radiation of frequency E E h falls on it then a it will not be absorbed at all b some of atoms will move to the first excited state c all atoms will be excited to the n 2 state d all atoms will make a transition to the n 3 state

O Consider aiming a beam of free electrons towards free protons When they scatter an electron and a proton cannot combine to produce a H atom because of a energy conservation b simultaneously releasing energy in the from of radiation gh C explain th c momentum conservation nomentum conservation

The parallax of a far off planet as measured from the two diametric extremes on the equator of the earth is 2 0 minute If the radius of the earth is 6400 km find the distance of the planet from the earth Angle of parallax 2 minute

on 49 When an electron falls from a higher energy to a lower energy level the difference in the energies appears in the form of Madia a electromagnetic radiation only b thermal radiation only EM W only c both electromagnetic and thermal radiations d none of these 55

A projectile is thrown from a point O on the ground at an angle 45 from the vertical and with a speed 5 2 m s The projectile at the highest point of its trajectory splits into two equal parts One part falls vertically down to the ground 0 5 s after the splitting The other part t seconds after the splitting falls to the ground at a distance x meters from the point O The acceleration due to gravity g 10 m s 5 The value of t is

Let three be a spherically symmetric charge distribution with charge density varying as p r Po 5 r upto r R and p r 0 for r R where r is the distance from the origin The electric field at a distance r r R from the origin is given by 4 R

If the earth rotates faster than its present speed the weight of an object will Question Type Single Correct Type 1 2 3 A Increase at the equator but remain unchanged at the poles Decrease at the equator but remain unchanged at the poles Remain unchanged at the equator but decrease at the poles Remain unchanged at the equator but

Find M in kg for which m will start sliding over m Table on which m and m are placed is smooth u is the friction coefficient between m and m Given m 2 kg m 1 kg u 0 5 g 10 m s m III

1 e force 5t N is applied on a block as shown in figure where t is time in second If coefficient of friction force between block and surface is then find the time in sec at which block just starts to move 3 F 5t m 6kg

inductor and a bulb are connected in series with a dc source A soft iron core is then inserted in the uctor What will happen to intensity of the bulb A Intensity of the bulb remains the same B Intensity of the bulb decreases C Intensity of the bulb increases D The bulb