Basic Physics Questions and Answers

A block slides on a vertical curved track of radius R 1 m If the speed of the block at point A is 2 m s then the normal force exerted by the block on the track at A is g 10 m s 2 kg A O 10 N O 20 N O 18 N O 28 N

R 37 The distance between the sun and the earth be r then the angular momentum of the earth around the sun is proportional to UP CPMT 2012 a r c T 3 2 r b d None of these P 1 ophorical planet has a mass M and diameter D

A diode detector is used to detect an amplitude modulated wave of 60 modulation by using a condenser of capacity 250 pico farad in parallel with a load resistance 100 kilo ohm Find the maximum modulated frequency which could be detected by it 2013 A 10 62 kHz B 5 31 MHz C 5 31 kHz D 10 62 MHz

0 A coil takes a current of 5 A from a 20 V d c supply When connected to a 200 V 50 Hz a c supply the current is 25 A Calculate the a resistance b impedance and c inductance of the coil

3 13 m s 4 9 m s 28 A block of 10 g slides on smooth horizontal surface with 20 m s towards a spring of spring constant 100 N m placed horizontally as shown in figure The maximum compression in spring is v 20 m s 10 g 1 2 m 3 20 m oooooo 2 0 2 m 4 m

What is the quantitation of charges What is the charging by induction Define 1 C charge using Coulomb s Law and how many equivalent charges are requir for it How many electrons will have a total charge of 1C

7 A 40 F capacitor in series with a coil of resistance 8 N and inductance 80 mH is connected to a 200 V 100 Hz supply Calculate a the circuit impedance b the current flowing c the phase angle between voltage and current d the voltage across the coil and e the voltage across the capacitor f real power g reactive power and h apparent power

In a vernier caliper a divisions of vernier scale are equal to bdivisions of main scale in which length of one division is 1 mm The least count of the instrument V C is a b a b a 810 a mm mm mm 4

2T Two waves given by y A sin vt x V A sin vt x superimpose on each other Amplitude of resultant wave for x X 6 is Options 1 A B 2 A B 2 Y B sin 2 vt x x and 3 VA B AB 4 VA B AB

ving magnetic field A rectangular coil expands on pulling from two diagonal edges in a region of magnetic field and no emf is induced in the coil This can be because of NCERT Pg 230 1 Magnetic field is constant 2 Magnetic field is in the plane of rectangular coil 3 Magnetic field has a perpendicular component to the plane of coil whose magnitude is decreasing 4 There is a uniform magnetic field perpendicular to plane of coil

A cyclist turns her bicycle upside down to tinker with it After she gets it upside down she notices the front wheel executing a show small amplitude back and forth rotational motion with a period of 12 s Considering the wheel to be a thin ring of mass 600 g and radius 30 cm whose only irregularity is the presence of the small tire valve stem determine the mass of the valve stem in gram Take n g and appropriate approximation

A hunter fires bullets of 10 gm with a gun of 5 kg at the speed of 400 m s If the hunter is standing on the ice surface with his gun the recoil velocity of the hunter will be the weight of the hunter is 75 kg

400 cm of liquid is put into the measuring cylinder The total mass of the measuring cylinder and the liquid is 560 g Four solid objects are lowered in turn into the liquid The densities of the objects are sh 1 0 40g cm 2 0 90 g cm 3 1 2g cm 4 2 7 g cm Which objects will float in the liquid A 1 only B 1 and 2 only C 1 2 and 3 D 3 and 4 only

nal having dielectric constant K 1 5 has the same area as of a plates of 3 parallel plate capacitor but has thickness of plate separation is introduced between the plates of the capacitor having capacitance C On introducing slab capacity becomes factor of NCERT Pg 78 1 2 c 2 C 3 6 c C 4 C 4

Two thin symmetrical lenses of different nature and of different materials have equal radii of curvature R 15 cm The lenses are put close together and immersed in water w 4 3 The focal length of system in water is 30 cm The difference between refractive indices of two lenses is 3 1 IN 13 3

Figure shows a circular area of radius R where a uniform magnetic field B is going into the plane of paper and increasing in magnitude at a constant rate In that case which of the following graphs drawn schematically correctly shows the variation of the induced electric field E r E C E R R B D E R R X X XX X X 2014

20 3 88 8 pF 4 73 3 pF A parallel plate capacitor is to be designed with a voltage rating of 2 kV using a material of dielectric constant 3 and dielectric strength about 12 x 106 Vm for safety we should like the field never exceed 20 of dielectric strength What minimum area of plate is required to have capacitance of 60 pF NCERT Pg 91 1 1 2 x 10 m 2 4 75 x 10 m 3 1 88 x 10 m 4 5 65 x 10 m

A boat is moving due east in a region where the earth s magnetic field is 5 0x10 NA m due north and horizontal The boat carries a vertical aerial 2m long If the speed of the boat is 1 50 ms the magnitude of the induced emf in the wire of aerial is 2011 A 0 75 mV C 0 15 mV B 0 50 mV D 1 mV

A large perfect cube of ice sits in the merciless Australian sun It is melting Each of its edges shrinks at 6 mm min How quickly does the volume of the ice cube decrease when it weighs 343 kg Hint Assume that the specific volume of ice is the same as that of liquid water which in turn we assume to be 1 litre kg 1000 cm kg O 882 0 kg min O2058 0 kg min O205 8 kg min O 8820 kg min O 88 2 kg min O205800 0 kg min O 29 4 kg min O 2 94 kg min O 8 82 kg min O 2940 0 kg min

nt S ix In a series LCR circuit R 12002 and it has resonant frequency 4000 rad sec At resonance the voltage across resistance and inductance is 60V and 40V respectively Find the value of L and C in circuit 20mH 25 F1

VI In a long straight solenoid with cross sectional radius a and number of turns per unit length n a current varies with a constant velocity I ampere per second Find the magnitude of the induced electric field strength as a function of the distance r from the solenoid axis Draw the approximate plot of this function For r a ruonl and for r a 1 a onl 2 r

In the circuit diagram shown initially there is no energ in the inductor and the capacitor The switch is closed at t 0 Find the current I as a function of time if R L C I R R V 000000 L C Figure 5 122 S

For the resistance network shown in the figure choose the correct option s Aa zefy ufadu Icah fay ud faccu PI 29 S 202 www 402 1 A PO B C D 19 102 492 12 V T 202 ww 22 The current through PQ is zero 6 2 A 2 Correct Answer Your Answer 1 3 A Correct Answer Your Answer The potential at S is less than that at Q z fa4a Correct Answer

vi An inductor coil a capacitor and an AC source of 24V are connected in series When the frequency of the source is varied a maximum current of 6A is observed If the inductor coil is connected to a battery of emf 12V and internal resistance 40 what will be steady state current through battery 1 5A1

Ray Optics and Optical Instruments 17 Find the position of the image formed by lens combination with convex lens of focal length 10 cm and concave lens of focal length 12 cm The object is kept at 30 cm from the convex lens as shown NCERT Pg 330 30 cm 1 36 cm to right of convex lens 2 36 cm to right of concave lens OX K6 cm 16 cm to left of concave lens tions 4 20 cm 125

xi A closed circuit consists of a source of constant EMFE and a choke coil of inductance L connected in series The active resistance of the whole circuit is equal to R At the moment t 0 the choke coil inductance was decreased n n 1 times suddenly Find the current in the circuit as a function of t nRi L 1 n 1 e 201

The apparent depth of water in cylindrical water tank of diameter 2R cm is reducing at the rate of X cm minute when water is being drained out at a constant rate The amount of water drained in c c per minute is n refractive index of air n2 refractive index of water a X b XMA n c 2mAnjing

8T Given system is in equilibrium All surfaces are smooth Spring is ideal and blocks are sticked at the ends of spring Now F is removed Average normal contact force between wat and mass m upto the time spring attains its natural length for the first time in Newton is Given that Fo Newton m K voorrrrrr m F

12 For the pipe used in the resonance in air column experiment of 340 m s upon excitation with a tuning fork of 512 Hz the length of the pipe corresponding to fundamental and the second resonance lengths respectively is with sound speed O 0 498 m and 0 166 m 0 166 m and 0 332 m O 0 332 m and 0 664 m 0 166 m and 0 498 m 1 F

Figure shows three sections of a circuit each section consisting of a wire along a circular arc and two long straight wires that are tangential to the arc all with same radius In A the straight wires pass each other without touching The sections carry equal currents GP P B A C In which case the magnitude of the magnetic field produced at the centre of curvature P is a greatest b least

ed gs gs it a ch iv A plane spiral with a great number N of turns wound tightly to one another is located in a uniform magnetic field perpendicular to the spiral s plane The outside radius of the spiral s turns is equal to a The magnetic induction varies with time as B Bo sin oot where Bo and are constants Find the amplitude of induced EMF in the spiral 0 Na B m 1

A measuring cylinder containing only water is placed on an electronic balance A small irregul shaped stone is now completely immersed in the water The diagrams show the equipment before and after the stone is immersed measuring cylinder balance water cm 100 90 80 70 60 50 40 30 20 10 105 0 g before the stone is immersed What is the density of the material of the stone A 1 7g cm B 3 3g cm C 4 5g cm cm 100 90 80 70 60 50 30 217 5g after the stone is immersed D 8 7 g cm stone

ILLUSTRATION 2 45 3 M A thin plano convex lens A has material of refractive index A 1 8 and its curved surface has radius of curvature R A thin layer of transparent material B is laid over the curved surface of A The refractive index of B is ug 1 2 and the curved surface of B that is not touching A has radius R of curvature This surface of B is silvered A point 1 2 object is kept at a distance of 10 cm on the principal axis of the system above the plane surface and its image is formed at a distance of 40 cm above the plane surface Find R

Which of the following statement s is are true for a solution containing 30 g urea in 100 g wat Kr for water 1 9 C kg mol and Kb for water 0 5 C kg mol A Its relative lowering of vapour pressure is 1 20 B Its freezing point is 9 5 C C Its boiling point is 2 5 C D van t Hoff factor for urea in aqueous solution is 1 2

if B vector makes an angle of 53 degree C vector makes an angle 37 degree wi th x axis and magnitude of A vector an d C vector is equal to 10 5 respectivel y then the magnitude of B vector is A vector B vector C vector 0

E R R a the initial currents through each resistor after the switch is closed C b c steady state currents through each resistor after the switch is closed final energy stored in the capacitor after the switch is closed 1 A time constant of the circuit when switch is opened K time constant of the circuit when switch is closed harged to 2090 V It is now disch

A planet has two small satellites in circular orbits around the planet The first satellite has a period T and an orbital radius of r The second satellite has a period of 1 5 What is the orbital radius of the second satellite OA2 1 53 B2 15n Ocn 1 5 OD n 1 5 En 1 5 1 5

A uniform rope of length 2 m is suspended as shown In figure If 8 53 then the radius of curvature at metres where a and E a lowest point of the rope is are co prime numbers Find the value of a b 4

Q 1 The wavelength of radiation absorbed during a particular spectroscopic transition is observed to be 15 m Express this in frequency Hz and in wavenumber cm and calculate the energy change during the transition in joules per molecule If the energy change were twice as large what would be the wavelength of the corresponding radiation

Q85 In a YDSE bi chromatic light of wavelengths 400 nm and 560 nm are used The distance between the slits is 0 1 mm and the distance between the plane of the slits and the screen is 1m The minimum distance between two successive regions of complete darkness is 1 4 mm 2 5 6 mm 3 14 mm 4 28 mm 1 From NCERT 3

How much force is exerted on a gunner by the machine gun when the gunner fires machine gun and 500 bullets per minute are fired The mass of bullet is 10g and it moves at 400 m s so as to avoid recoil

Vp Ns A radio can tune over the frequency range 800 1200 kHz If LC circuit has an effective inductance of 200 H What should be the range of its variable capacitor INCERT Pg 266 2 88 pF 198 pF 4 200 DF 400 DE 100 pF 280 pF ons 3 40 pF 80 pF

Question No 34 The electron is present in the 1 51 eV energy state for H atom The radius of orbit of electron in this orbit is about O 0 53 A O 2 38 A O 1 59 A O4 77 A

to measure small currents A certain galvanometer has a resistance 500 and gives a full scale deflection for a current of 200 A This meter is connected as shown in the figure to make a multirange current meter S B MEC 500 S ww R The value of R is Cq B w R circuit R WA X Connection to the circuit is made at the terminals shown The currents in the external circuit needed to give full scale deflections when X is connected to A B and C in turn are shown in the table 31 fed X connected to Current in the external circuit mA A TC OYVE 1 10 100 Hel 2 SOCIA

The value of a for which the vectors 21 35 7k and 31 j ak are parallel is c golveLancer 1 d 7 a 2 12 b 8 SolveLancer SolveLancer Test SolveLancer Test SolveLancer Test Test SolveLancer SolveLancer T Test Test SolveLancer Test SolveLancer Test Solve 10

19 A pair of adjacent coils has mutual inductance of 1 5 H If the current in one coil changes from 0 to 10 A in 0 5 s the rate of change of flux linkage with other coil is 1 20 V 3 4 V NCERT Pg 219 2 30 V 4 5 V

Which of the following gates correspond to the truth table given below ABY 0 elekr 0 0 0 1 1 0 1 1 1 1 ONAND O NOR OR AND

5 A long solenoid is of length 1 25 m and 600 turns per unit length It is connected to a source which establishes a current of 2A in circuit Magnetic energy stored in the solenoid coil with cross sectional area 0 1 m is INCERT Pg 224 1 0 1 J 3 0 6 J 2 0 4 J 4 1 2 J

ctor A steady current of 2 A flowing through resistor produces a heat of 100 W produce a heat of 400 W by supplying an current through the same circuit the va of peak current will be NCERT Pg 2 1 4 A 3 2 8 A 2 5 6 A 4 8 A

0 A man pulls a bucket full of water from h metre deep well If the mass of rope is m and mass of bucket f of water is M then work done by the man is 1 3 M 2 M an mgh 2 4 M m 2 gh m ob