Basic Physics Questions and Answers

If radius of a nitrogen molecule to be roughly 1 0 then mean free path of nitrogen molecule in a cylinder containing nitrogen at 2 atm and temperature 17 C Molecular mass of nitrogen 28 g is 1 0 10 m 3 5 5 m 2 0 20 m

18 The figure shows a particle experiencing a force as it moves in the presence of a uniform magnetic field directed out of the page What is the charge of the particle A Positive B Negative C Neutral V

32 In the circuit shown there is a box containing a resistance R and inductance L and a capacitor of capacitance C connected in series to an alternating source of angular frequency 4 rad s Box has power factor and the circuit has 3 overall power factor 1 The impedance of the box is 1 3 2 C 4C 4 3

qual and S1 ese is 1 NI 2 On th e 16 Two rods one is semi circular of thermal conductivity K and other is straight of thermal conductivity K2 and of same cross sectional area are joined as shown in figure The point A and B are maintained at same temperature difference If K rate of flow of heat is same in two rods then is 1 2 A B K

Two springs with spring constants k 1500 N m and k 3000 N m are stretched by the same force The ratio of potential energy stored in the springs will be 1 2 1 2 1 2 3 4 1 4 1 4

where Tmax Tmin If length of string is 1 4 L 1 10 m s 2 20 m s Velocity at highest point is Tmax 10 m m Tmin 3 Maximum tension in the st Minimum tension in the strin 10 3 1 2 m s 4 10 3 m s 4

In a Rutherford a scattering experiment when a projectile of charge Z and mass M approaches a target nucleus of charge Z and mass M the distance of closest approach is t The energy of the projectile is 1 directly proportional to M x M 2 directly proportional to Z Z 3 directly proportional to Z 4 directly proportional to mass M The Bohr model of Atom

1 45 In the figure 1 411 shown the charge Q is fixed Another charge 2q and mass Mis projected from a distance R from the fixed charge Minimum separation between the two charges if times of the projected velocity at 1 the velocity becomes 3 this moment is given as A R 2 C R Q R Figure 1 411 30 B 3 R 29 D None of these

7 A spring block system undergoes simple harmonic motion on smooth horizontal surface The block is now given some positive charge and a uniform horizontal electric field to the right is switched on as a result of moooo E 1 The time period of oscillation will increase 2 The time period of oscillation will remains unaffected 3 The mean position of simple harmonic motion will shift to the right 4 Both 2 and 3

One end of cylindrical glass 1 5 is given a shape of concave refracting surface of radius of curvature 10 cm as shown in the figure An air bubble is situated in glass rod at a point on its axis such that it appears to be at 10 cm from surface inside glass The actual location of bubble inside glass from surface is 1 5 Bubble 12 cm 20 cm 30 cm 36 cm R 10 cm

On bombarding a beam of a particles on atom of gold foil a few particles get defle whereas most of them go straight and rem undeflected This is due to 1 The nucleus occupy much smaller vol as compared to the volume of atom 2 The force of repulsion on fast movin particles is very small 3 The neutrons in the mucleus do not have effect of a particles 4 The force of attraction on a particles by oppositely charged electron is not suffie

34 The number of photons emitted per second by monochromatic light of 60 W source of wavelength 5000 A is 1 1 5 1020 3 3 5 1020 2 1 5 10 18 4 3 5 10 18 35 The ratio of magnetic dipole moment to angular momentum in a hydrogen like atom is

1 A submarine experience a pressure of 5 05 10 Pa at a depth of d in a sea When it goes further to a depth of d it experiences a pressure of 8 08 10 Pa then d d is approximately density of water 10 kg m acceleration due to gravity 10 ms 2 2019 Main 10 Apr II and a 500 m b 400 m c 600 m d 300 m

In YDSE of equal width slits the intensity of 10th maximum is found to be Io the intensity at AD distance from central maximum will be 4d Symbols have their usual meanings 1 2 21 430 2 4 10 4

A car is travelling along a road at constant speed u 7 00 ms The driver sees a stoplight ahead change to amber and applies the brakes Consequently the car experiences a total resistive force equal to of its weight and stops just at the stoplight Taking g 9 81 ms2 how far does the car travel during the braking period

0 Two moving coil galvanometers M and M2 have the following particulars N 30 B 0 25 T A 7 2 x 10 3 m G 100 and N2 60 B2 0 50 T A2 1 8 x 10 m G 502 respectively The spring G2 constants are identical to both galvanometers The ratio of their current sensitivity is NCERT Pg 173 1 1 1 2 2 1 3 4 1 4 1 4

22 Expansion of liquid on heating is different from that solids since expansion of liquid is 1 More than solids because molecular spacing in them is less 2 More than solids because molecular spacing in them is more 3 Less than solid because molecular spacing in them is more 4 Less than solids because molecular spacing in them is less

A block of mass 2 kg moving with velocity of 10 m s on a smooth surface hits a spring of force constant 80 10 N m as shown The maximum compression in the spring is 10 m s m 1 5 cm 2 10 cm 3 15 cm 4 20 cm 00000000

3 The force F on a sphere of radius a moving in a medium with velocity v is given by F 6nav The dimensions of nare CBSE PMT 1997 DPMT 2000 1 MLT 1 3 MLT 2 2 MT 4 ML 3 ansions of

At a certain place a freely suspended magnetic needle makes 20 oscillations per minute At another place where the magnetic field is 4 times time period of same needle will be NCERT Pg 178 2 1 s 4 3 s 1 10 s 3 1 5 s

Three different objects of masses m m2 and m3 are allowed to fall from rest and from the same point O along three different frictionless paths The speeds of the three objects on reaching the ground will be in the ratio of 1 m m m3 2 m 2m2 3m3 3 1 1 1 4 m1 1 m2 m3

A closely wound solenoid of 3000 turns and area of cross section 1 6 104 m carrying a current of 5 0 A is suspended through its centre Magnetic moment associated with the solenoid is NCERT Pg 2011 1 12 8 A m 2 5 6 A m 3 4 8 A m

When a body moves with a constant speed along a circle 1 No work is done on it 2 No acceleration is produced in the body 3 No force acts on the body 4 Its velocity remains constant 1 2 3 A

In an experiment with a potentiometer V 10V R is adjusted to be 500 A student wanting B to measure voltage E of a battery approx 8V finds no null point possible He then diminshes R to 1002 and is able to locate the null point on the last 4th segment of the potentiometer The resistance of the potentiometer wire R will be a R b Find the value of 1 a V E AH E 2 N OOM

A balloon starts from rest and rises up with constant net acceleration of 10ms After 2s a particle drops from the balloon After further 1s match the following g 10m s Column I Column II A Height of particle from ground P 10 SI units B Speed of particle Q 15 SI units C Dispalcement of particle R 35 SI units D Acceleration of partical S Upward T Down ward

EXAMPLE 1 Preeti reached the metro station and found that the escalator was not working She walked up the stationary escalator in time t On other days if she remains stationary on the moving escalator then escalator takes her up in time t The time taken by her to walk up on the moving escalator will be NEET 2017 d t t a t t 2 b tit t t c t t t t

1 j and k are unit vectors along x y and z axes respectively the angle 0 between the vector i j k and vector i is given by A 0 cos B sin C sin D 0 cos 3 2 2 1 G

Two particles 1 and 2 move with constant velocities V and V At the initial momen their radius vectors are equal to i and How must these four vectors be interrelated for the particles to collide A C V V E V V V V V V G E V V 1 D None of these B v

Fig below shows the wave y Asin wt kx at any instant travelling in the ve x direction What is the magnitude of the slope of the curve at B Question Type Single Correct Type 1 w A 2 3 k A y in B KA

Question a Which material is the best conductor among Gold Iron and Nichrome Why b You are given five shapes made of same material a rod a thin sheet and a cube Which shape has more resistivity Why

If Assertion is false and Reason is 7 Assertion If a body is thrown upwards the distance covered by it in the last second of upward motion is above 5 m irrespective of its initial speed Reason The distance covered in the last second of upward direction is equal to the covered in the first second of downward motion when the particle is dropped

A neutron having kinetic energy E collides with singly ionised He atom at rest and move along initial direction Which of the following statement s is are true for the above mentioned collision A Collision will be perfectly inelastic if E 17 eV B Collision will be perfectly inelastic is Eo 8 16 eV C If E then ploton of wavelength 500 nm is observed just after the collision if Eo 8 16 eV D Perfectly elastic collision is not possible

of A proton is moving with speed 2 105 m s 1 enters a uniform magnetic field B 1 5 T At the entry velocity vector makes an angle of 30 to the direction of the magnetic field The pitch of helical path it describes is nearly NCERT Pg 138 1 6 25 mm 2 4 37 mm 3 7 25 mm

A boat can move with a speed of 5 km h in still water A river is flowing with a speed of 3 km h and having a width of 10 km The minimum time taken for a round trip to the exact same point is A 1 hr B 2 hr C 3 hr D 4 hr Solution D Given VBr 5 km h V 3 km h For the minimum time of round trip he should cross perpendicular to the river While going V VBr 0 VBr 4 m s B V A Velocity of boat with respect to river VBr in the direction perpendicular to the river is given by V V 5 3 Br

evidence of the molecular motion 1 Brownian motion 2 Diffusion 3 Evaporation 4 All of these

The position vector of a particle r a cos ti a sin tj The Velocity the particle is A Parallel to position Vector B Perpendicular to position vector C Directed towards origin D Directed away from the origin

4 A wire having a linear mass density 5 0 10 kg m is stretched between two rigid supports with tension of 450 N The wire resonates at frequency 400 Hz The next higher frequency at which the wire resonates is 500 Hz The length of the wire will be 1 1 m 3 4 5 m 2 4 m 4 1 5 m

6 A particle moves along a straight line OX At a time t in sec the distance x in metre of the particle from O is given by X 40 12t t How long would the particle travel before coming to rest

790 Midi K Phy Section A This section contains 20 SINGLE CORRECT TYPE questions Each question has 4 choices 1 2 3 Read More For diamagnetic substances the magnetic susceptibility is O Negative and small Positive and small hr min Negative and large Positive and large

sider the beam shown in Figure 1 Suppose that 3 m re 1 of 1 W kN m Express your answer to three significant figures and include the appropriate units Enter positive value if the force is upward and negative value if the force is downward FR Submit Part B Value Units My Answers Give Up Determine the equivalent couple moment at point O Express your answer to three significant figures and include the appropriate units Enter positive value if the moment is counterclockwise and negative value if the moment is clockwise

eplace the distributed loading by an equivalent sultant force Suppose that w 3 4 kN m and w 2 kN m Figure 1 gure 1 of 1 W 3m 4 m B W x Express your answer to three significant figures and include the appropriate units FR Submit Part B Ti A Value Units My Answers Give Up Determine the direction angle of the resultant force measured counterclockwise from the negative direction Express your answer using three significant figures IVO AXO vec

4 x 3 3cos 2nt 10 Particle A and B are dropped to fall towards the earth from a height 2 Re R radius of earth from surface of earth If the particles are dropped simultaneously but from two locations which are slightly away from one another then the separation between the particles ignore gravitational interaction between the particles 1 Decrease 2 Increase 3 Remains same

If a galvanometer is converted into voltmeter with help of 3202 resistance then voltage range becomes n times of initial If same galvanometer is converted into ammeter with help of 202 resistance as a shunt then current range become n times of initial Find resistance in 2 of original galvanometer

3 c Capacitance area b Capacitance unit length Potential length A certain charge is divided in the ratio x y so that when kept at a given distance the force is maximum The ratio x a 2 1 b 4 1 1 1 d 3 1 4 The work done in moving a 1c charge from A to B in a triangle of ABC of side m as shown in fig is

13 The gravitational field at some point in space is g 31 4 N kg The force exerted on a 2 kg mass placed at a point is 1 10 N 53 with x axis 2 10 N 37 with x axis 3 7 N 53 with x axis 4 7 N 37 with x axis

A ball is suspended by a thread of length What minimum horizontal velocity has to be imparted to the ball for it to reach the height of the suspension 1 gl 2 2 gl 3 gl 4 2gl

An indian submarine is moving in the Arabian sea with constant velocity To detect enemy it sends T in water Initially the waves are getting m out sonar waves which travel with velocity 1050 reflected from a fixed island and the reflected waves are coming back to submarine The frequency of reflected waves are detected by the submarine and found to be 10 greater than the sent waves Now an enemy ship comes in front due to which the frequency of reflected waves detected by submarine becomes 21 greater than the sent waves Q The velocity of enemy ship should be Indian submarine Sonar waves Fixed island

A particle is projected at an angle 45 from a point lying 2 m from the foot of a wall It just touches the top of the wall and falls on the ground 4 m from it The height of the wall is A C 4321 m m B m D ww m

A signal monitored from the vibration activities of the ground earth tremor is defined as X t Cos w t 0 Find the frequency in Hz of the signal x t and its period Also find the energy and the power of the signal

In the following mass pulley systems shown in figure 1 and figure 2 two blocks A and B are connected as shown Find the possible correct relation s between their velocities a In figure 1 and figure 2 B 3 VA b In figure 1 and figure 2 VB VA 3 and V 2 VA c constraint equation in figure 1 is VB 3V 0 d constraint equation is figure 2 is VB 2V 0 food to A Figure 1 B Figure 2