50278 + Interview Questions in Physics

1.	A trolley containing water has total mass of 4000 kg and is moving at a speed of 40 m/s. Now water starts coming out of a hole from the bottom of the trolley at the rate of 8 kg/s. Speed of trolley after 50 s is
Answer» A trolley containing water has total mass of $4000 kg$ and is moving at a speed of $40 m/s$ . Now water starts coming out of a hole from the bottom of the trolley at the rate of $8 kg/s$ . Speed of trolley after $50 s$ is

Discussion

2.	The ratio of speed of sound in neon to that in water vapours at any temerature(when molecular weight of neon is 2.02x10^{-2}kg mol^{-1} and for water vapours is 1.8x10^{-2} kg/mol). is how much
Answer» The ratio of speed of sound in neon to that in water vapours at any temerature(when molecular weight of neon is 2.02x10^{-2}kg mol^{-1} and for water vapours is 1.8x10^{-2} kg/mol). is how much

Discussion

3.	22.The dependence of pressure on volume of a gas is shown. Draw the temperature vs volume graph.
Answer» 22.The dependence of pressure on volume of a gas is shown. Draw the temperature vs volume graph.

Discussion

4.	The position vectors of four points A,B,C and D are^i+^j+^k,2^i+5^j,3^i+2^j−3^k,^i−6^j−^k respectively. Then select the correct relation.
Answer» The position vectors of four points A,B,C and D are $^i +^j +^k, 2^i + 5^j, 3^i + 2^j - 3^k,^i - 6^j -^k$ respectively. Then select the correct relation.

Discussion

5.	Answer the following: (a) The top of the atmosphere is at about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about 100 Vm−1. Why then do we not get an electric shock as we step out of our house into the open? (Assume the house to be a steel cage so there is no field inside!) (b) A man fixes outside his house one evening a two metre high insulating slab carrying on its top a large aluminium sheet of area 1m2. Will he get an electric shock if he touches the metal sheet next morning? (c) The discharging current in the atmosphere due to the small conductivity of air is known to be 1800 A on an average over the globe. Why then does the atmosphere not discharge itself completely in due course and become electrically neutral? In other words, what keeps the atmosphere charged? (d) What are the forms of energy into which the electrical energy of the atmosphere is dissipated during a lightning? (Hint: The earth has an electric field of about 100 Vm−1 at its surface in the downward direction, corresponding to a surface charge density = −10−9 C m−2. Due to the slight conductivity of the atmosphere up to about 50 km (beyond which it is good conductor), about + 1800 C is pumped every second into the earth as a whole. The earth, however, does not get discharged since thunderstorms and lightning occurring continually all over the globe pump an equal amount of negative charge on the earth.)
Answer» Answer the following: (a) The top of the atmosphere is at about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about 100 Vm⁻¹. Why then do we not get an electric shock as we step out of our house into the open? (Assume the house to be a steel cage so there is no field inside!) (b) A man fixes outside his house one evening a two metre high insulating slab carrying on its top a large aluminium sheet of area 1m². Will he get an electric shock if he touches the metal sheet next morning? (c) The discharging current in the atmosphere due to the small conductivity of air is known to be 1800 A on an average over the globe. Why then does the atmosphere not discharge itself completely in due course and become electrically neutral? In other words, what keeps the atmosphere charged? (d) What are the forms of energy into which the electrical energy of the atmosphere is dissipated during a lightning? (Hint: The earth has an electric field of about 100 Vm⁻¹ at its surface in the downward direction, corresponding to a surface charge density = −10⁻⁹ C m⁻². Due to the slight conductivity of the atmosphere up to about 50 km (beyond which it is good conductor), about + 1800 C is pumped every second into the earth as a whole. The earth, however, does not get discharged since thunderstorms and lightning occurring continually all over the globe pump an equal amount of negative charge on the earth.)

5.

Answer the following: (a) The top of the atmosphere is at about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about 100 Vm−1. Why then do we not get an electric shock as we step out of our house into the open? (Assume the house to be a steel cage so there is no field inside!) (b) A man fixes outside his house one evening a two metre high insulating slab carrying on its top a large aluminium sheet of area 1m2. Will he get an electric shock if he touches the metal sheet next morning? (c) The discharging current in the atmosphere due to the small conductivity of air is known to be 1800 A on an average over the globe. Why then does the atmosphere not discharge itself completely in due course and become electrically neutral? In other words, what keeps the atmosphere charged? (d) What are the forms of energy into which the electrical energy of the atmosphere is dissipated during a lightning? (Hint: The earth has an electric field of about 100 Vm−1 at its surface in the downward direction, corresponding to a surface charge density = −10−9 C m−2. Due to the slight conductivity of the atmosphere up to about 50 km (beyond which it is good conductor), about + 1800 C is pumped every second into the earth as a whole. The earth, however, does not get discharged since thunderstorms and lightning occurring continually all over the globe pump an equal amount of negative charge on the earth.)

Answer»

Answer
the following:

(a) The top
of the atmosphere is at about 400 kV with respect to the surface of
the earth, corresponding to an electric field that decreases with
altitude. Near the surface of the earth, the field is about 100 Vm⁻¹.
Why then do we not get an electric shock as we step out of our house
into the open? (Assume the house to be a steel cage so there is no
field inside!)

(b) A man
fixes outside his house one evening a two metre high insulating slab
carrying on its top a large aluminium sheet of area 1m².
Will he get an electric shock if he touches the metal sheet next
morning?

(c) The
discharging current in the atmosphere due to the small conductivity
of air is known to be 1800 A on an average over the globe. Why then
does the atmosphere not discharge itself completely in due course and
become electrically neutral? In other words, what keeps the
atmosphere charged?

(d) What
are the forms of energy into which the electrical energy of the
atmosphere is dissipated during a lightning? (Hint: The earth has an
electric field of about 100 Vm⁻¹
at its surface in the downward direction, corresponding to a surface
charge density = −10⁻⁹
C m⁻².
Due to the slight conductivity of the atmosphere up to about 50 km
(beyond which it is good conductor), about + 1800 C is pumped every
second into the earth as a whole. The earth, however, does not get
discharged since thunderstorms and lightning occurring continually
all over the globe pump an equal amount of negative charge on the
earth.)

Discussion

6.	143.Two soap bubbles coalesce. It is noticed that while joining together radius of two bubbles are a and b (a>b) . Then the radius of curvature of interface between the two bubbles will be ?? In terms of a and b ??
Answer» 143.Two soap bubbles coalesce. It is noticed that while joining together radius of two bubbles are a and b (a>b) . Then the radius of curvature of interface between the two bubbles will be ?? In terms of a and b ??

Discussion

7.	A taxi leaves the station X for station Y every 10 minutes. Simultaneously, a taxi leaves station Y also for station X every 10 minutes. The taxis move at the same constant speed and go from X to Y or vice-versa in 2 hours. How many taxis coming from the other side will each taxi meet enroute from Y to XA. 10B. 11C. 12D. 23
Answer» A taxi leaves the station X for station Y every 10 minutes. Simultaneously, a taxi leaves station Y also for station X every 10 minutes. The taxis move at the same constant speed and go from X to Y or vice-versa in 2 hours. How many taxis coming from the other side will each taxi meet enroute from Y to X A. 10 B. 11 C. 12 D. 23

Discussion

8.	43. idth of a river is 30 m, river velocity is 4m/s and rowing velocity of boatman is 5m/s.How long time will it take him to row 10m up the river and then back to his starting point??
Answer» 43. idth of a river is 30 m, river velocity is 4m/s and rowing velocity of boatman is 5m/s.How long time will it take him to row 10m up the river and then back to his starting point??

Discussion

9.	In the figure shown, what minimum force ‘F′ should be applied perpendicular to the top face of the block for it to not move? Given the coefficient of static friction between the plane and the block =0.5. Take g=10 m/s2
Answer» In the figure shown, what minimum force $‘ F^{'}$ should be applied perpendicular to the top face of the block for it to not move? Given the coefficient of static friction between the plane and the block $= 0.5$ . Take $g = 10 {m/s}^{2}$

Discussion

10.	Two spherical balls A and B made of the same material, are heated to the same temperature. They are then placed in identical surroundings. If the diameter of A is twice that of B, the ratio of rates of cooling of A and B will be
Answer» Two spherical balls A and B made of the same material, are heated to the same temperature. They are then placed in identical surroundings. If the diameter of A is twice that of B, the ratio of rates of cooling of A and B will be

Discussion

11.	The angle of projection when the range is equal tothe distance through which the particle would haveto fall in order to acquire a velocity equal to itsvelocity of projection.(1) 30^° (2) 75^° 45^° (4) 60^°
Answer» The angle of projection when the range is equal tothe distance through which the particle would haveto fall in order to acquire a velocity equal to itsvelocity of projection.(1) 30^° (2) 75^° 45^° (4) 60^°

Discussion

12.	Phase difference between a particle at a compression and a particle at successive rarefaction is
Answer» Phase difference between a particle at a compression and a particle at successive rarefaction is

Discussion

13.	A car moves linearly with uniform retardation. If the car covers 40 m in the last 2 seconds of its motion ,what is the velocity of the car at the beginning of the last second ?
Answer» A car moves linearly with uniform retardation. If the car covers 40 m in the last 2 seconds of its motion ,what is the velocity of the car at the beginning of the last second ?

Discussion

14.	Q) The length of a string is 100cm . The frequencies of two consecutive harmonics formed on the string are 300 Hz and 400Hz respectively. The maximum amplitude is 10cm when the string oscillates with its fundamental frequency . Write the expression of stationary wave in this case.
Answer» Q) The length of a string is 100cm . The frequencies of two consecutive harmonics formed on the string are 300 Hz and 400Hz respectively. The maximum amplitude is 10cm when the string oscillates with its fundamental frequency . Write the expression of stationary wave in this case.

Discussion

15.	If y=tan[log(x2)], then dydx is -
Answer» If $y = tan [log (x^{2})]$ , then $\frac{d y}{d x}$ is -

Discussion

16.	A tiny ball of mass m is initially at rest atheight H above a cake of uniform thickness h.At some moment the particle falls freely,touches the cake surface and then penetratesin it at such a constant rate that its speedbecomes zero on just reaching the ground(bottom of the cake). Speed of the ball at theinstant it touches the cake surface and itsretardation inside the cake are respectively
Answer» A tiny ball of mass m is initially at rest atheight H above a cake of uniform thickness h.At some moment the particle falls freely,touches the cake surface and then penetratesin it at such a constant rate that its speedbecomes zero on just reaching the ground(bottom of the cake). Speed of the ball at theinstant it touches the cake surface and itsretardation inside the cake are respectively

Discussion

17.	How focal lengths are different for each other
Answer» How focal lengths are different for each other

Discussion

18.	Resistance of a solution (A) is 50 ohm and that of a solution (B) is 100 ohm, both solution being taken in the same conductivity cell. If equal volume of solution (A) and (B) are mixed, what will be the resistance of the mixture, using the same cell?Assume thta there is no increase in the degree of dissociation of (A) and (B) on mixing.
Answer» Resistance of a solution (A) is $50 ohm$ and that of a solution (B) is $100 ohm$ , both solution being taken in the same conductivity cell. If equal volume of solution (A) and (B) are mixed, what will be the resistance of the mixture, using the same cell? Assume thta there is no increase in the degree of dissociation of (A) and (B) on mixing.

Discussion

19.	A steel rod 100 cm long is clamped at its middle. The fundamental frequency of longitudinal vibrations of the rod are given to be 2.53 kHz. What is the speed of sound in steel?
Answer» A steel rod 100 cm long is clamped at its middle. The fundamental frequency of longitudinal vibrations of the rod are given to be 2.53 kHz. What is the speed of sound in steel?

Discussion

20.	A particle of charge −16×10−18 C moving with velocity 10 ms−1 along the X-axis enters region where a magnetic field of induction B is along the Y-axis and an electric field of magnitude 104 V/m is along the negative Z-axis. If the charged particle continues moving along the X-axis, the magnitude of B is -
Answer» A particle of charge $- 16 \times 10^{- 18} C$ moving with velocity $10 {ms}^{- 1}$ along the X-axis enters region where a magnetic field of induction $B$ is along the Y-axis and an electric field of magnitude $10^{4} V/m$ is along the negative Z-axis. If the charged particle continues moving along the X-axis, the magnitude of $B$ is -

Discussion

21.	If a current of 0.5ampere flows through a metallic wire for 2 hours, then how manyelectrons would flow through the wire?
Answer» If a current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons would flow through the wire?

Discussion

22.	4) Move undelectea in regiot-l10.) A charged particle enters a magnetic field at right angles to the magnetic field. The field exists for a lengthequal to 1.5 times the radius of circular path of the particle. The particle will be deviated from its path by(1) 90(3) 30^° (2) sin-1 Z(4) 180^°
Answer» 4) Move undelectea in regiot-l10.) A charged particle enters a magnetic field at right angles to the magnetic field. The field exists for a lengthequal to 1.5 times the radius of circular path of the particle. The particle will be deviated from its path by(1) 90(3) 30^° (2) sin-1 Z(4) 180^°

Discussion

23.	A ray of light passes from vacuum into a medium of refractive index μ,the angle of incidence is found to be twice the angle of refraction. Then the angle of incidence is
Answer» A ray of light passes from vacuum into a medium of refractive index $μ$ ,the angle of incidence is found to be twice the angle of refraction. Then the angle of incidence is

Discussion

24.	A plank with mass M=6 kg rests on top of two identical, solid, cylindrical rollers that have radius R=4 cm and mass m=2 kg. The plank is pulled by a constant horizontal force →F of magnitude 6 N applied to the end of the plank and perpendicular to the axes of the cylinders (which are parallel). The cylinders roll without slipping on the flat surface. Also, there is no slipping between the cylinders and the plank.The total friction acting on the plank in newton is (answer upto two decimal places)
Answer» A plank with mass $M = 6 k g$ rests on top of two identical, solid, cylindrical rollers that have radius $R = 4 c m$ and mass $m = 2 k g$ . The plank is pulled by a constant horizontal force $\to F$ of magnitude 6 $N$ applied to the end of the plank and perpendicular to the axes of the cylinders (which are parallel). The cylinders roll without slipping on the flat surface. Also, there is no slipping between the cylinders and the plank. The total friction acting on the plank in newton is (answer upto two decimal places)

Discussion

25.	A refrigerator consumes an average 35 W power to operate between temperature −10∘C to 25∘C. If there is no loss of energy, then how much average heat per second does it transfer ?
Answer» A refrigerator consumes an average $35 W$ power to operate between temperature $- 10^{\circ} C$ to $25^{\circ} C$ . If there is no loss of energy, then how much average heat per second does it transfer ?

Discussion

26.	Seawater at a frequency f=9×102 Hz, has permittivity ε=80ε0 and resistivity ρ=0.25 Ωm. Imagine a parallel plate capacitor is immersed in seawater and is driven by an alternating voltage source V(t)=V0 sin(2πft). Then, the conduction current between the plates becomes 10x times the displacement current after time t=1/800 s. The value of x (integer only) is
Answer» Seawater at a frequency $f = 9 \times 10^{2} Hz$ , has permittivity $ε = 80 ε_{0}$ and resistivity $ρ = 0.25 Ω m$ . Imagine a parallel plate capacitor is immersed in seawater and is driven by an alternating voltage source $V (t) = V_{0} sin (2 π f t)$ . Then, the conduction current between the plates becomes $10^{x}$ times the displacement current after time $t = 1 / 800 s$ . The value of $x$ (integer only) is

Discussion

27.	A converging and a diverging lens of focal lengths are placed coaxially in contact .find the power and focal length of combination
Answer» A converging and a diverging lens of focal lengths are placed coaxially in contact .find the power and focal length of combination

Discussion

28.	If x(t) be a signal with Nyquist rate 100 Hz. The Nyquist rate for the signal x(t) cos100πt is ___Hz. 200
Answer» If x(t) be a signal with Nyquist rate 100 Hz. The Nyquist rate for the signal $x (t) c o s 100 π t$ is ___Hz. 200

Discussion

29.	An inductor of inductance, L=5 H is connected to an AC source having voltage, V=10sin(10t+π6). Find the inductive reactance.
Answer» An inductor of inductance, $L = 5 H$ is connected to an AC source having voltage, $V = 10 sin (10 t + \frac{π}{6})$ . Find the inductive reactance.

Discussion

30.	A point charge 100 nC is at a distance 2 mm directly above the center of a square of side 5 cm of a cube.What is the magnitude of the electric flux through the square?
Answer» A point charge 100 nC is at a distance 2 mm directly above the center of a square of side 5 cm of a cube.What is the magnitude of the electric flux through the square?

Discussion

31.	A certain amount of an ideal gas is initially at a pressure P1 and temperature T1. First, it undergoes an isobaric process 1 - 2 such that T2=3T14. Then, it undergoes an isochoric process 2→3 such that T3=T22. The ratio of the final volume to the initial volume of the ideal gas is
Answer» A certain amount of an ideal gas is initially at a pressure $P_{1}$ and temperature $T_{1}$ . First, it undergoes an isobaric process 1 - 2 such that $T_{2} = \frac{3 T_{1}}{4}$ . Then, it undergoes an isochoric process $2 \to 3$ such that $T_{3} = \frac{T_{2}}{2}$ . The ratio of the final volume to the initial volume of the ideal gas is

Discussion

32.	a point particle of mass m moves along the uniformly rough track PQR the cofficient of friction between the particle and the rough track equals μ.the particle is released from rest ,from the point p and it come to rest at a point R the energies lost by the ball over tthe parts PQ and QR of the track are equal to each other and no energy is lost when particle change direction from PQ to qR the values of the cofficient of friction μ and dis†an ce
Answer» a point particle of mass m moves along the uniformly rough track PQR the cofficient of friction between the particle and the rough track equals μ.the particle is released from rest ,from the point p and it come to rest at a point R the energies lost by the ball over tthe parts PQ and QR of the track are equal to each other and no energy is lost when particle change direction from PQ to qR the values of the cofficient of friction μ and dis†an ce

Discussion

33.	An iron ring of relative permeability 'µ' has windings of insulated copper wire of n turns per metre. When the current in the windings is I, find the expression for the magnetic field in the ring.
Answer» An iron ring of relative permeability 'µ' has windings of insulated copper wire of n turns per metre. When the current in the windings is I, find the expression for the magnetic field in the ring.

Discussion

34.	A particle executes linear simple harmonic motion with an amplitude of 3 cm. When the particle is at 2 cm from the mean position, the magnitude of its velocity is equal to that of its acceleration. Find the time period in seconds.
Answer» A particle executes linear simple harmonic motion with an amplitude of $3 cm$ . When the particle is at $2 cm$ from the mean position, the magnitude of its velocity is equal to that of its acceleration. Find the time period in seconds.

Discussion

35.	If 'u' is instaneous velocity of particle and 'v' is velocity of wave,then 1)'u' is instantaneous to 'v' 2)u is parallel to v 3)\|u\| is equal to \|v\| 4)\|u\|=( slope of waveform)\|v\|
Answer» If 'u' is instaneous velocity of particle and 'v' is velocity of wave,then 1)'u' is instantaneous to 'v' 2)u is parallel to v 3)\|u\| is equal to \|v\| 4)\|u\|=( slope of waveform)\|v\|

Discussion

36.	An ammeter is made by shunting a 30 ohm galvanometer with a 30 ohm resis†an ce. What additional shunt should be connected across it to double the range? (1) 5 ohm (2) 10 ohm (3) 15 ohm (4) 30 oh
Answer» An ammeter is made by shunting a 30 ohm galvanometer with a 30 ohm resis†an ce. What additional shunt should be connected across it to double the range? (1) 5 ohm (2) 10 ohm (3) 15 ohm (4) 30 oh

Discussion

37.	A 12 V battery connected to a 6 Ω, 10 H coil through a switch drives a constant current in the circuit. The switch is suddenly opened. Assuming that it took 1 ms to open the switch, The average emf induced across the coil is-
Answer» A $12 V$ battery connected to a $6 Ω$ , $10 H$ coil through a switch drives a constant current in the circuit. The switch is suddenly opened. Assuming that it took $1 ms$ to open the switch, The average emf induced across the coil is-

Discussion

38.	Four particles of masses 1 g,2 g,3 g and 4 g are kept at points (0,0),(0,3 cm),(3 cm,3 cm),(3 cm,0) respectively. Find the moment of inertia of the system of particles (in g-cm2) about z axis.
Answer» Four particles of masses $1 g, 2 g, 3 g$ and $4 g$ are kept at points $(0, 0), (0, 3 cm), (3 cm, 3 cm), (3 cm, 0)$ respectively. Find the moment of inertia of the system of particles (in ${g-cm}^{2}$ ) about $z$ axis.

Discussion

39.	A square plate of edge d and a circular disc of diameter d are placed touching each other at the midpoint of an edge of the plate as shown in figure (9-Q2).Locate the centre of mass of the combination,assuming same mass per unit area for the two plates.
Answer» A square plate of edge d and a circular disc of diameter d are placed touching each other at the midpoint of an edge of the plate as shown in figure (9-Q2).Locate the centre of mass of the combination,assuming same mass per unit area for the two plates.

Discussion

40.	what is maxwell four equation and energy density?
Answer» what is maxwell four equation and energy density?

Discussion

41.	The system shown in fig. is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of the spring k=40Nm−1andg=10ms−2 ).
Answer» The system shown in fig. is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of the spring $k = 40 N m^{- 1} a n d g = 10 m s^{- 2}$ ).

41.

The system shown in fig. is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of the spring k=40Nm−1andg=10ms−2 ).

Answer»

The system shown in fig. is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of the spring $k = 40 N m^{- 1} a n d g = 10 m s^{- 2}$ ).

Discussion

42.	A simple pendulum has time period T1 when it is on earth's surface and T2 when it is taken at height 2R above the earth surface calculate T2/T1.(R is the radius of earth
Answer» A simple pendulum has time period T1 when it is on earth's surface and T2 when it is taken at height 2R above the earth surface calculate T2/T1.(R is the radius of earth

Discussion

43.	Tap the bubbles which are quadrantal angles.
Answer» Tap the bubbles which are quadrantal angles.

Discussion

44.	The electric potential varies in space according to the relation V=3x+4y. A particle of mass 0.1kg starts from rest from point (2,3.2) under the influence of this field. The charge on the particle is +1μC. Assume V and (x,y) are in S.I. unitsThe velocity of the particle when it crosses the x - axis is
Answer» The electric potential varies in space according to the relation $V = 3 x + 4 y .$ A particle of mass $0.1 k g$ starts from rest from point $(2, 3.2)$ under the influence of this field. The charge on the particle is $+ 1 μ C .$ Assume V and $(x, y)$ are in S.I. units The velocity of the particle when it crosses the x - axis is

Discussion

45.	An electron jumps from n = 4 to n = 1 state in H-atom. The recoil momentum of H-atom (in eV/C) is
Answer» An electron jumps from n = 4 to n = 1 state in H-atom. The recoil momentum of H-atom (in eV/C) is

Discussion

46.	A boat that has a speed of 5 km/hr in still water crosses a river of width 1 km along the shortest possible path in 20 minutes. The velocity of the river water in (km/hr) is
Answer» A boat that has a speed of $5 km/hr$ in still water crosses a river of width $1 km$ along the shortest possible path in $20$ minutes. The velocity of the river water in $(km/hr)$ is

Discussion

47.	A steady electric current is flowing through a cylindrical wire:- (a)the electric feild at the axis of wire is zero (b)the magnectic feild at the axis of the wire is zero (c)the electric feild in the vicnity of wire is zero (d)the magnectic feild in the vicnity of wire is zero. (1)a,b,c (2)b,c (3)only c (4)only b
Answer» A steady electric current is flowing through a cylindrical wire:- (a)the electric feild at the axis of wire is zero (b)the magnectic feild at the axis of the wire is zero (c)the electric feild in the vicnity of wire is zero (d)the magnectic feild in the vicnity of wire is zero. (1)a,b,c (2)b,c (3)only c (4)only b

Discussion

48.	ntFind the capacitance if a spherical capacitor is given a charge Q and inner sphere is grounded?n
Answer» ntFind the capacitance if a spherical capacitor is given a charge Q and inner sphere is grounded?n

Discussion

49.	An inclined plane makes as angle θ0=30∘ with the horizontal. A particle is projected from this plane with a speed of 5 m/s at an angle of elevation β=30∘ with the horizontal as shown in the figure.Find the range of the particle on the plane when it strikes the plane. (Assume the incline is long enough and g=10 m/s2)
Answer» An inclined plane makes as angle $θ_{0} = 30^{\circ}$ with the horizontal. A particle is projected from this plane with a speed of $5 m/s$ at an angle of elevation $β = 30^{\circ}$ with the horizontal as shown in the figure. Find the range of the particle on the plane when it strikes the plane. (Assume the incline is long enough and $g = 10 {m/s}^{2}$ )

Discussion

50.	43.50 ml of hydrogen diffuses out through a small hole of a vessel in 20 minutes m. The time taken by 40 ml of oxygen to diffuse out is
Answer» 43.50 ml of hydrogen diffuses out through a small hole of a vessel in 20 minutes m. The time taken by 40 ml of oxygen to diffuse out is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A trolley containing water has total mass of 4000 kg and is moving at a speed of 40 m/s. Now water starts coming out of a hole from the bottom of the trolley at the rate of 8 kg/s. Speed of trolley after 50 s is

The ratio of speed of sound in neon to that in water vapours at any temerature(when molecular weight of neon is 2.02x10^{-2}kg mol^{-1} and for water vapours is 1.8x10^{-2} kg/mol). is how much

22.The dependence of pressure on volume of a gas is shown. Draw the temperature vs volume graph.

The position vectors of four points A,B,C and D are^i+^j+^k,2^i+5^j,3^i+2^j−3^k,^i−6^j−^k respectively. Then select the correct relation.

143.Two soap bubbles coalesce. It is noticed that while joining together radius of two bubbles are a and b (a>b) . Then the radius of curvature of interface between the two bubbles will be ?? In terms of a and b ??

43. idth of a river is 30 m, river velocity is 4m/s and rowing velocity of boatman is 5m/s.How long time will it take him to row 10m up the river and then back to his starting point??

In the figure shown, what minimum force ‘F′ should be applied perpendicular to the top face of the block for it to not move? Given the coefficient of static friction between the plane and the block =0.5. Take g=10 m/s2

Two spherical balls A and B made of the same material, are heated to the same temperature. They are then placed in identical surroundings. If the diameter of A is twice that of B, the ratio of rates of cooling of A and B will be

The angle of projection when the range is equal tothe distance through which the particle would haveto fall in order to acquire a velocity equal to itsvelocity of projection.(1) 30^° (2) 75^° 45^° (4) 60^°

Phase difference between a particle at a compression and a particle at successive rarefaction is

A car moves linearly with uniform retardation. If the car covers 40 m in the last 2 seconds of its motion ,what is the velocity of the car at the beginning of the last second ?

Q) The length of a string is 100cm . The frequencies of two consecutive harmonics formed on the string are 300 Hz and 400Hz respectively. The maximum amplitude is 10cm when the string oscillates with its fundamental frequency . Write the expression of stationary wave in this case.

If y=tan[log(x2)], then dydx is -

How focal lengths are different for each other

A steel rod 100 cm long is clamped at its middle. The fundamental frequency of longitudinal vibrations of the rod are given to be 2.53 kHz. What is the speed of sound in steel?

If a current of 0.5ampere flows through a metallic wire for 2 hours, then how manyelectrons would flow through the wire?

4) Move undelectea in regiot-l10.) A charged particle enters a magnetic field at right angles to the magnetic field. The field exists for a lengthequal to 1.5 times the radius of circular path of the particle. The particle will be deviated from its path by(1) 90(3) 30^° (2) sin-1 Z(4) 180^°

A ray of light passes from vacuum into a medium of refractive index μ,the angle of incidence is found to be twice the angle of refraction. Then the angle of incidence is

A refrigerator consumes an average 35 W power to operate between temperature −10∘C to 25∘C. If there is no loss of energy, then how much average heat per second does it transfer ?

A converging and a diverging lens of focal lengths are placed coaxially in contact .find the power and focal length of combination

If x(t) be a signal with Nyquist rate 100 Hz. The Nyquist rate for the signal x(t) cos100πt is ___Hz. 200

An inductor of inductance, L=5 H is connected to an AC source having voltage, V=10sin(10t+π6). Find the inductive reactance.

A point charge 100 nC is at a distance 2 mm directly above the center of a square of side 5 cm of a cube.What is the magnitude of the electric flux through the square?

A certain amount of an ideal gas is initially at a pressure P1 and temperature T1. First, it undergoes an isobaric process 1 - 2 such that T2=3T14. Then, it undergoes an isochoric process 2→3 such that T3=T22. The ratio of the final volume to the initial volume of the ideal gas is

An iron ring of relative permeability 'µ' has windings of insulated copper wire of n turns per metre. When the current in the windings is I, find the expression for the magnetic field in the ring.

A particle executes linear simple harmonic motion with an amplitude of 3 cm. When the particle is at 2 cm from the mean position, the magnitude of its velocity is equal to that of its acceleration. Find the time period in seconds.

If 'u' is instaneous velocity of particle and 'v' is velocity of wave,then 1)'u' is instantaneous to 'v' 2)u is parallel to v 3)|u| is equal to |v| 4)|u|=( slope of waveform)|v|

An ammeter is made by shunting a 30 ohm galvanometer with a 30 ohm resis†an ce. What additional shunt should be connected across it to double the range? (1) 5 ohm (2) 10 ohm (3) 15 ohm (4) 30 oh

A 12 V battery connected to a 6 Ω, 10 H coil through a switch drives a constant current in the circuit. The switch is suddenly opened. Assuming that it took 1 ms to open the switch, The average emf induced across the coil is-

Four particles of masses 1 g,2 g,3 g and 4 g are kept at points (0,0),(0,3 cm),(3 cm,3 cm),(3 cm,0) respectively. Find the moment of inertia of the system of particles (in g-cm2) about z axis.

A square plate of edge d and a circular disc of diameter d are placed touching each other at the midpoint of an edge of the plate as shown in figure (9-Q2).Locate the centre of mass of the combination,assuming same mass per unit area for the two plates.

what is maxwell four equation and energy density?

The system shown in fig. is released from rest with mass 2 kg in contact with the ground. Pulley and spring are massless, and friction is absent everywhere. The speed of 5 kg block when 2 kg block leaves the contact with the ground is (force constant of the spring k=40Nm−1andg=10ms−2 ).

A simple pendulum has time period T1 when it is on earth's surface and T2 when it is taken at height 2R above the earth surface calculate T2/T1.(R is the radius of earth

Tap the bubbles which are quadrantal angles.

An electron jumps from n = 4 to n = 1 state in H-atom. The recoil momentum of H-atom (in eV/C) is

A boat that has a speed of 5 km/hr in still water crosses a river of width 1 km along the shortest possible path in 20 minutes. The velocity of the river water in (km/hr) is

ntFind the capacitance if a spherical capacitor is given a charge Q and inner sphere is grounded?n

43.50 ml of hydrogen diffuses out through a small hole of a vessel in 20 minutes m. The time taken by 40 ml of oxygen to diffuse out is