Basic Physics Questions and Answers

Why does the scientist astronaut in a space station in space feel weightless O the astronaut s acceleration is zero O the astronaut is falling O this is a psychological effect associated with rapid motion O the astronaut is beyond the range of the earth s gravity O the astronaut is at a point in space where the effects of the moon s gravity and the earth s gravity car

A projectile is going to be launched in a trajectory 44 degrees above the horizontal from a point at an elevation of 11 meters it must hit a point located 28 meters to the right and 4 meters above the initial position Determine the horizontal distance traveled m to two decimal places when it reaches the maximum elevation

1 Rank the magnitude of value of B dl for the closed paths shown in figure from the smallest to largest 1 abcd 3 adch 2A 2A a b O 3A 2 acdb 4 achd

Subject Chemistry When the transmittance of a solution is measured in a cell that has a light path length of 1 cm a value of 85 is obtained What will the percentage transmittance be la 1 the 1

The equivalent resistance between A and B in the arrangement of resistances as shown is A A 4r B 3r C 2 5r D r 2r www mm r ww fuiy win ww 2r ww im

Consider two smooth blocks A and B of mass 1 kg each Among the given situations the force between the blocks will be maximum in 2N 2N B A 2 N B A 2N B A B A

Equal number of identical cells of internal resistance r each are once joined i series and then in parallel The strength of the current through an external resistor R will be same in both the cases if A R 2r B R r 2 C R r D 2R r

4b Beams of high speed protons can be produced in guns using electric fields to accelerate the protons a Wh acceleration would a proton experience if the gun s electric field were 2 00 104 N C b What speed would the proto attain if the field accelerated the proton through a distance of 1 00 cm

A particle is projected vertically upward with velocity from the top of tower of height H Its velocity at a depth h below the point of projection is thrice of its velocity at a height h above the point of projection The time at which it hit the ground is V 2 Hg 9 1 2H 9 29H

charge on the shell is 10 C what is the charge a on the inner surface of the shell and b of the particle 5b A thin walled metal spherical shell has radius 25 0 cm and charge 2 00 10 7 C Find E for a point a inside the shel b just outside it and c 3 00 m from the center

Consider the set of vectors 1 1 0 0 1 1 and 1 0 1 a The three vectors are orthonormal b The three vectors are linearly independent c The three vectors cannot form a basis in a three dimensional real vector space d 1 1 0 1 1 1 0 can be written as a linear combination of 1 0 1 1 and 1 0 1

A light cylindrical vessel is kept on a horizontal surface Its base area is A A A hole of cross section 50 the side wall just at its bottom Minimum coefficient of friction such that it does not slide due to thrust force of emerging liquid is Select one 1 0 08 2 0 2 3 0 5 4 0 04 is made on

An increase in pressure of 20 kPa cause a certain volume of liquid decrease by 2 x 10 3 percentage of initial volume The speed of sound wave in liquid is nearly kg Density of liquid 2 10 500 m s 700 m s 850 m s 920 m s m

43 A 220 V ac supply is connected between the two points A and B as shown in the figure The output waveform across the diode is A MA til 1 3 Vo 00000 t Axt www teee 2 V01 Vo to Vo 4 t

In the figure all ropes and pulleys are massless and frictionless The spring constant k 2 N m Initially the 5kg block is held at rest such that the 4kg block is resting on floor and spring is unextented then it is released What is the 5kg block s speed just when 4kg block is about to lift off the floor A 5 5 m s C 2 10 m s B 7 5 m s D 5 10 m s wee 4kg 5kg

The velocity time graph of a particle moving along a fixed direction is as shown in figure The average velocity of the particle between time intervals 5 s to 10 s is A 0 5 10 12 7 5 m s 6 m s 4 0 12 m s 4 m s t s

assag The length of a potentiometer wire is 600cm and it carries a current of 40mA For a cell of emf 2V and internal resistance 100 the null point is found to be at 500cmn On connecting a voltmeter across the cell the balancing length is decreases by 10cm The voltmeter reading will be a 1 96V b 1 8V c 1 64V d 0 96V The resistance of the voltmeter a 5000 b 290 c 49 d 200

Dielectric materials increases potential difference which applied between the plates of capacitors Dielectric material increases capacity of capacitance Net electric field after insertion of dielectric material between plates is E Eo E whereE E are the induced electric field and external electric field respectively a i ii are correct i b i ii iii are correct c ii iii are correct d None of these Which are correct for electric current

In an infinite flat layer of thickness of h the spherical cavity in diameter of h figure is cut out Find the intensity of electric field at points A and B if the layer is uniformly charged with volume charge density of p Also find potential difference VA VB A EA ph 680 B E ph 380 B C VA VB ph 24 D V VB ph 880

9V www 252 8Q wwww 252 852 www wwww 252 402 In the given circuit the curren through A the 3 2 resistor is 0 50 A B the 4 2 resistor is 0 50 A C the 3 2 resistor is 0 25 A D the 4 resistor is 0 25 A

A rocket has a mass of 20000 kg of which 16000 kg is fuel The rocket engine can exhaust fuel at the rate of 200 kg s with an exhaust velocity of 3000 m s relative to the rocket Find the net force acting on the rocket 10 second after blast off Take g 10 m s 1 4 2 10 N 2 6 10 N 3 18 10 N 4 zero

In the two cords and the accelerations of the blocks in figure 2 22 if friction is negligible The pulleys are 200 gm m 500 gm and massless and frictionless m 400 gm Take g 10 m s m3 loto aizviena arti m 40 sied has G da to opozoo sit a lex Figure 2 22 m2 Bolgmaxs 140 N v Fin 2 26 a

The work function of the cathode of a photocell in a circuit is 6 10 19 J Ultraviolet wave of wavelength 250 nm hits the cathode perpendicularly If we change the frequency of the radiation at most by what factor can the linear momentum of the emitted electron be greater than that of the entering photon Take h 6 6 x 10 34 J sec m 9 10 3 kg

In YDSE the screen is at distance D from the plane of the slits and slits are illuminated by monochromatic light of wavelength A Pis a point on screen at distance y from central maxima If by some arrangement the slits be moved symmetrical apart with relative velocity v the number of fringes crossing the point P per unit time will be yv 21 D yD V D vy

An uniform electric field E 10 N c as shown in figure find VA VB A 2m B a 10Volt b 10Volt c 20Volt d 20Volt 2m 2m a C E

The focal length of a plano convex lens is 20 cm The plane face of it is silvered An object is placed at a distance of 60 cm from the lens on its axis on the convex side Then the distance ir cm of the image is A 120 C 40 B 30 D 60

A resistor of resistance R is connected in series with wire AB of identical resistance across a battery as shown in fig If half of the length of wire AB is cut and removed and circuit is completed again the new reading of voltmeter will be V 2 4 213124316 times than earlier times than earlier times than earlier times than earlier E R A B

and a dielectric slab of dielectric constant K 4 is inserted between the plates Simultaneously the distance between the plates reduced to half then Page 2 When battery is removed after charging then capacitance and electric field becomes respectively a Capacitance 8 times and electric field times 8 b Capacitance 8 times and electric field times c Capacitance times and electric field 8 times 8

0 Electric current is vector quantity ii Average current is when potential not applied between conductor Page 1 Electric current more more cross sectional area and more speed less cross sectional area iii a i ii iii are correct b ii is correct

Two fixed charges 2Q and Q are located at the points with coordinates 3a 0 and 3a 0 in the x y plane Find the locus of all points in the x y plane where the electric potential due to the charges is zero A C x y 10ax 9a 0 Correct Answer B x 2y 10ax 9a 0 2 2x y 10ax 9a 0 D x y 20ax 9a 0

A monkey of mass m is sitting on a platform of mass M Monkey can jump with a velocity of 5 m s making an angle 37 with the horizontal with respect to platform To jump the monkey 1 meter with respect to the ground Find out the value of m M

A small metal ball falls vertically and strikes a fixed smooth plane inclined to horizontal at an angle less than 45 The ball rebounds horizontally If m be the mass of the ball and u be the speed of the ball before impact and e is coefficient of restitution then rebound speed of the ball eu loss of KE in the ball ism 1 e u impulse of the plane during collision is 1 emu

In which of the following cases an object can be considered as point object NCERT Pg 55 1 Length of train in comparison to platform 2 Length of engine in comparison to length of a small bridge 3 A spinning cricket ball that turns sharply on hitting the pitch 4 A railway carriage moving without jerks

Repeat your calculation of the energy levels of the Bohr atom but now assume that the potential energy is given by U r e 4 r o r where o is a positive constant Assume that angular momentum is quantized Letr be bohr radius and E be ground level energy in bohr atom Letr be radius of new atom and E be ground level energy in new atom Choose CORRECT option A I I E E B r ro E E C r ro E E

A reflecting surface PQ is fixed and a parallel beam of light is incident on it The intensity of light is 600 W m and it makes an angle 53 with the vertical line The area of surface PQ is 2 0 m It is observed that 50 incident energy is reflected by the reflecting surface PQ The net force exerted by the beam on the surface in N is X

A heavy box is being pushed across the floor It s causing some trouble because the floor is not very smooth Identify the forces involved Sketch a free body diagram of the box iii If the weight of the box is 40 kg and the applied force is 900 N calculate the values of all the forces

U TI parlat Mai KS Tor Selecony each comfect option o 2 In case if selected typed option is incorrect 0 In case if no response is typed selected Two springs P and Q have force constants k and k such that k k The work done in stretching the two springs more for spring P than for spring Q when they are stretched by the same force more for spring P than for spring q when they are stretched by the same amount more for spring P than for spring Q when they are stretched by the same amount but more for spring Q when they are stretched by the same force more for spring Q when they are stretched by the same amount

If denotes a unit vector along an incident ray a unit vector along the refracted ray into a medium of refractive index u and a unit vector normal to the boundary of the media directed towards the incident medium then the law of refraction can be written as 11 1 n rn 2 x xr 4 x rxn 3 x rxn

Which of the following molecules are expected to exhibit pre dominantly inter molecular H bonding ii Salicyclic acid iv o boric acid i Acetic acid iii m nitrophenol v Para hydroxy benzaldehyde 1 i ii iii iv only 3 i ii iii iv v 2 i iii iv only 4 i iii iv v only

A coil of radius 1 cm and of turns 100 is placed in the middle of a long solenoid of radius 5 cm and having 5 turns cm parallel to the axis of solenoid The mutual inductance in millihenery will be 1 0 0316 2 0 063 3 0 105 4 Zero

to earth s magnetic field charged comic particles 1 Require greater kinetic energy to reach the equator than the poles 2 Require less kinetic energy to reach the equator than the poles 3 Can never reach the equator 4 Can never reach the poles

Which of the following order is incorrect as per the properties mentioned against each 1 K Na Ca Mg density 2 Li Na K Rb Cs Melting point 3 Be Mg2 Ca Sr Ba Hydration Energy 4 Mg Ca Sr Ba Be Reducing operty in aqueous medium

ransparent cube contains a small air bubble Its apparent distance is 2 cm when see through one face and 5 cm when seen through other face If the refractive index of the mater of the cube is 1 5 the real length of the edge of cube must be 1 7 cm 2 7 5 cm 3 10 5 cm 4 14 3 cm

A cylinder of compressed air has the capacity to 10 m3 and contains air at 10 atm and 27 C A sudden leak causes a drop in pressure at 5 0 atm Assuming this is a reversible adiabatic event determine The loss of mass in kg in the tank

If the current in a coil of resistance R decreases according to i t graph shown in the figure then find the total heat produced in the coil is 1 3 Rt 5 Rt io to t 2 4 iRt 4 Rt

The ray model can be used to explain which of the following properties of light Part A O Diffraction and reflection Diffraction refraction and reflection O Refraction and reflection Diffraction and refraction

Two friends Ram and Shyam both decided to visit a temple on a hill Both of them can move up the hill to the temple in 3 00 h and down hill in 1 00 h Ram started at 12 noon but Shyam started when Ram had already covered one third of the distance up the hill If both of them move at their full capabilities when they will meet en route Assume no stay at the temple A 2 45 PM B 3 00 PM C 3 15 PM D 3 45 PM

Set up a system of linear equations representing the network shown in Figure 7 26 In a network it is assumed that the total flow into a junction blue circle is equal to the total flow out of the junction 20 X 1 10 Figure 7 26 31 Ny X1 10 X4

Using monochromatic light of wavelength 2 an experimentalist sets up the Young s double slit experiment in three ways as shown If she observes that y the wavelength of light used is D Transparent mica sheet of thickness t 1 8 m 1 6 1 580 pm Central fringe Fringe width 2D Central fringe O Fringe width B Screen Central fringe Fringe width B 2 560 pm

01 A spherical shell with an inner radius a and an outer radius b is made of conducting material A point charge Q is placed at the centre of the spherical shell and a total charge q is placed on the shell The charge is distributed on the surfaces as 1 Q on the inner surface q on the surface 2 Q on the inner surface q Q on surface the outer on Telegram ne 3 Q on the inner surface q Q on the outer surface 4 The charge q is spread uniformly between the