50278 + Interview Questions in Physics

1.	A light bulb is rated at 125 W for a 250 V a.c., supply. Calculate the resistance of the bulb.
Answer» A light bulb is rated at 125 W for a 250 V a.c., supply. Calculate the resistance of the bulb.

Discussion

2.	A body of mass 0.1 kg moving with a velocity of 10 m/s hits a spring (fixed at the other end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is
Answer» A body of mass 0.1 kg moving with a velocity of 10 m/s hits a spring (fixed at the other end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is

Discussion

3.	A solid body starts rotating about a stationary axis with an angular acceleration α = α0cos φ, φ is the angle of rotation from the initial position. Find the angular velocity of the body as a function of the angle φ.
Answer» A solid body starts rotating about a stationary axis with an angular acceleration $α = α_{0} c o s φ$ , $φ$ is the angle of rotation from the initial position. Find the angular velocity of the body as a function of the angle $φ$ .

3.

A solid body starts rotating about a stationary axis with an angular acceleration α = α0cos φ, φ is the angle of rotation from the initial position. Find the angular velocity of the body as a function of the angle φ.

Answer»

A solid body starts rotating about a stationary axis with an angular acceleration $α = α_{0} c o s φ$ , $φ$ is

the angle of rotation from the initial position. Find the angular velocity of the body as a function of the angle $φ$ .

Discussion

4.	(a) For a given AC, i=im sin ωt, show that the average power dissipated in a resistor R over a complete cycle is 12i2mR. (b) A light bulb is rated at 100W for a 220V AC supply. Calculate the resistance of the bulb.
Answer» (a) For a given AC, $i = i_{m} s i n ω t$ , show that the average power dissipated in a resistor $R$ over a complete cycle is $\frac{1}{2} i_{m}^{2} R$ . (b) A light bulb is rated at $100 W$ for a $220 V$ AC supply. Calculate the resistance of the bulb.

Discussion

5.	The loss of weight of a solid when immersed in a liquid at 0∘C is W0 then the loss of weight W at t∘C is - where α and β are the cubical expansion coefficients of solid and liquid respectively.
Answer» The loss of weight of a solid when immersed in a liquid at $0^{\circ} C$ is $W_{0}$ then the loss of weight W at $t^{\circ} C$ is - where $α$ and $β$ are the cubical expansion coefficients of solid and liquid respectively.

Discussion

6.	Which retinal cells are involved in colour vision?
Answer» Which retinal cells are involved in colour vision?

Discussion

7.	A convex lens of focal length 20 cm and a concave lens of focal length 10 cm are placed 10 cm apart with their principal axes coinciding. A beam of light travelling parallel to the principal axis and having a beam diameter 5.0 mm, is incident on the combination.. Show that the emergent beam is parallel to the incident one. Find the beam diameter of the emergent beam.
Answer» A convex lens of focal length 20 cm and a concave lens of focal length 10 cm are placed 10 cm apart with their principal axes coinciding. A beam of light travelling parallel to the principal axis and having a beam diameter 5.0 mm, is incident on the combination.. Show that the emergent beam is parallel to the incident one. Find the beam diameter of the emergent beam.

Discussion

8.	A parallel plate condenser with plate separation ‘d’ and plate area A is connected to a battery and charged to a potential V. Then the battery is disconnected and with insultated handles the plate separation is increased to 2d. Work done in the process will be?
Answer» A parallel plate condenser with plate separation ‘d’ and plate area A is connected to a battery and charged to a potential V. Then the battery is disconnected and with insultated handles the plate separation is increased to 2d. Work done in the process will be?

Discussion

9.	Differentiate y=cosec xcotx w.r.t x
Answer» Differentiate $y = cosec x cot x$ w.r.t $x$

Discussion

10.	The time constant of a capacitor is 5sec. If the capacitance is C=100nF and it is charged from zero by a cell of EMF 10V through a resistor. What is the charge on it after 3 seconds?
Answer» The time constant of a capacitor is 5sec. If the capacitance is C=100nF and it is charged from zero by a cell of EMF 10V through a resistor. What is the charge on it after 3 seconds?

Discussion

11.	In 2D plane , the equations of the partical's motion -- x= 5t2+2 , y= 2t2+5 ; Then, the motion path of the partical is --- a) parabola, b) circle, c) straight, d) hyperbola
Answer» In 2D plane , the equations of the partical's motion -- x= 5t²+2 , y= 2t²+5 ; Then, the motion path of the partical is --- a) parabola, b) circle, c) straight, d) hyperbola

Discussion

12.	A step up transformer operates on a 230V line and a load current of 2A. The ratio of the primray and secondary windings is 1 : 25. The current in the primary is
Answer» A step up transformer operates on a 230V line and a load current of 2A. The ratio of the primray and secondary windings is 1 : 25. The current in the primary is

Discussion

13.	Two particles A and B, each having a charge Q, are placed a distance d apart where should a particle of charge q be placed on the perpendicular bisector of AB so that it experiences maximum force ? What is the magnitude of this maximum force?
Answer» Two particles A and B, each having a charge Q, are placed a distance d apart where should a particle of charge q be placed on the perpendicular bisector of AB so that it experiences maximum force ? What is the magnitude of this maximum force?

Discussion

14.	Work done by a system under isothermal change from a volume V1 to V2 for a gas which obeys Vander Waal's equation (V−β n)(P+an2V)=nRT
Answer» Work done by a system under isothermal change from a volume $V_{1} t o V_{2}$ for a gas which obeys Vander Waal's equation $(V - β n) (P + \frac{a n^{2}}{V}) = n R T$

Discussion

15.	A trolley of mass 100 kg, starting from rest, describes 100 m in 10 seconds. At that instant, i.e. at the commencement of the 11th second, two packets, each of mass 12.5 kg, are gently placed on the trolley. How far (in m) does it move in the next 10 seconds assuming that the forces on the trolley remain the same throughout?
Answer» A trolley of mass $100 k g$ , starting from rest, describes $100 m$ in $10$ seconds. At that instant, i.e. at the commencement of the $11^{t h}$ second, two packets, each of mass $12.5 k g$ , are gently placed on the trolley. How far (in $m$ ) does it move in the next $10$ seconds assuming that the forces on the trolley remain the same throughout?

Discussion

16.	Discuss the use pattern of energy consumption in India.
Answer» Discuss the use pattern of energy consumption in India.

Discussion

17.	Which of the following may have coordinates of center of mass as (−a,−b), where a & b are positive constants.
Answer» Which of the following may have coordinates of center of mass as $(- a, - b)$ , where $a$ & $b$ are positive constants.

Discussion

18.	A uniform ladder of length 10.0 m and mass 16.0 kg is resting against a vertical wall making an angle of 37 ∘ with it. The vertical wall is frictionless but the ground is rough. An electrician weighing 60.0 kg climbs up the ladder. If he stays on the ladder at a point 8.00 m from the lower end, what will be the normal force and the force of friction on the ladder by the ground ? What should be the minimum coefficient of friction for the electrician to work safely ?
Answer» A uniform ladder of length 10.0 m and mass 16.0 kg is resting against a vertical wall making an angle of 37 $^{\circ}$ with it. The vertical wall is frictionless but the ground is rough. An electrician weighing 60.0 kg climbs up the ladder. If he stays on the ladder at a point 8.00 m from the lower end, what will be the normal force and the force of friction on the ladder by the ground ? What should be the minimum coefficient of friction for the electrician to work safely ?

Discussion

19.	Which of the following figures represents damped harmonic motion?
Answer» Which of the following figures represents damped harmonic motion?

Discussion

20.	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, ratio of the 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, ratio of the rates of cooling of A and B will be

Discussion

21.	Five identical cubes each of mass ‘m′ are on a straight line with two adjacent faces in contact on a horizontal surface as shown in the figure. Suppose the surface is frictionless and a constant force P is applied from left to right to the end face of A, then net force on each cube is
Answer» Five identical cubes each of mass $‘ m^{'}$ are on a straight line with two adjacent faces in contact on a horizontal surface as shown in the figure. Suppose the surface is frictionless and a constant force $P$ is applied from left to right to the end face of $A$ , then net force on each cube is

Discussion

22.	A long soleniod has 200 turns per cm and carries a current i. The magnetic field at its centre is 6.28×10−2 Weber/m2. Another long solenoid has 100 turns per cm and it carries a current i3 The value of the magnetic field at its centre is
Answer» A long soleniod has 200 turns per cm and carries a current i. The magnetic field at its centre is $6.28 \times 10^{- 2} W e b e r / m^{2}$ . Another long solenoid has 100 turns per cm and it carries a current $\frac{i}{3}$ The value of the magnetic field at its centre is

Discussion

23.	A rigid body of mass 'm' and radius 'r' rolls without slipping on a rough horizontal surface. A force is acting on a point 'x' distance from the center as shown in figure. Assuming the moment of inertia of the solid body about an axis through its COM be ICM. Find the value of x so that static friction is zero.
Answer» A rigid body of mass 'm' and radius 'r' rolls without slipping on a rough horizontal surface. A force is acting on a point 'x' distance from the center as shown in figure. Assuming the moment of inertia of the solid body about an axis through its COM be $I_{C M}$ . Find the value of x so that static friction is zero.

23.

A rigid body of mass 'm' and radius 'r' rolls without slipping on a rough horizontal surface. A force is acting on a point 'x' distance from the center as shown in figure. Assuming the moment of inertia of the solid body about an axis through its COM be ICM. Find the value of x so that static friction is zero.

Answer»

A rigid body of mass 'm' and radius 'r' rolls without slipping on a rough horizontal surface. A force is acting on a point 'x' distance from the center as shown in figure. Assuming the moment of inertia of the solid body about an axis through its COM be $I_{C M}$ . Find the value of x so that static friction is zero.

Discussion

24.	When 1 mole of A(g) is introduced in a closed rigid 1 litre vessel maintained at constant temperature the following equilibria are established A(g)⇌B(g)+C(g):KC1 C(g)⇌D(g)+B(g):KC2 The pressure at equilibrium is twice the initial pressure. Calculate the value of KC2KC1 if [C]eq[B]eq=15.
Answer» When 1 mole of A(g) is introduced in a closed rigid 1 litre vessel maintained at constant temperature the following equilibria are established $A (g) ⇌ B (g) + C (g) : K_{C_{1}}$ $C (g) ⇌ D (g) + B (g) : K_{C_{2}}$ The pressure at equilibrium is twice the initial pressure. Calculate the value of $\frac{K_{C_{2}}}{K_{C_{1}}}$ if $\frac{[C]_{e q}}{[B]_{e q}} = \frac{1}{5}$ .

Discussion

25.	The time period of a conical pendulum shown in figure is:
Answer» The time period of a conical pendulum shown in figure is:

25.

The time period of a conical pendulum shown in figure is:

Answer»

The time period of a conical pendulum shown in figure is:

Discussion

26.	The spectrum of radiation 1.0×1014Hz is in the infrared region. The energy of one photon of this in joules will be
Answer» The spectrum of radiation $1.0 \times 10^{14} H z$ is in the infrared region. The energy of one photon of this in joules will be

Discussion

27.	If heat is given to an ideal gas at constant pressure, then select the graph which best represents the variation of VT with temperature (T).
Answer» If heat is given to an ideal gas at constant pressure, then select the graph which best represents the variation of $V T$ with temperature $(T)$ .

Discussion

28.	Strip of wood of mass M and length l is placed on a smooth horizontal surface. An insect of mass m starts at one end of the strip and walks to the other end in time t, moving with a constant speed. Then the speed of the strip as seen from the ground is
Answer» Strip of wood of mass $M$ and length $l$ is placed on a smooth horizontal surface. An insect of mass $m$ starts at one end of the strip and walks to the other end in time $t$ , moving with a constant speed. Then the speed of the strip as seen from the ground is

Discussion

29.	A small sphere of radius r falls from rest in a viscous liquid. Heat is produced due to friction between the liquid and the sphere. Choose the correct relation between rate of production of heat and the radius of the sphere, when terminal velocity is attained.
Answer» A small sphere of radius $r$ falls from rest in a viscous liquid. Heat is produced due to friction between the liquid and the sphere. Choose the correct relation between rate of production of heat and the radius of the sphere, when terminal velocity is attained.

Discussion

30.	In the figure shown, the equivalent capacitance between ′A′ and ′B′ is:
Answer» In the figure shown, the equivalent capacitance between $^{'} A^{'}$ and $^{'} B^{'}$ is:

Discussion

31.	The power factor of a circuit in which a box having unknown electrical devices connected in series with a resistor of resistance 3 Ω is 35. The reactance of the box is
Answer» The power factor of a circuit in which a box having unknown electrical devices connected in series with a resistor of resistance $3 Ω$ is $\frac{3}{5}$ . The reactance of the box is

Discussion

32.	Two point masses A of mass M and B of mass 4M are fixed at the ends of a rod of length l and of negligible mass. The rod is set rotating about an axis perpendicular to its length with a uniform angular speed. The work required for rotating the rod will be minimum when the distance of axis of rotation from the mass A is at
Answer» Two point masses A of mass M and B of mass 4M are fixed at the ends of a rod of length l and of negligible mass. The rod is set rotating about an axis perpendicular to its length with a uniform angular speed. The work required for rotating the rod will be minimum when the distance of axis of rotation from the mass A is at

Discussion

33.	The radius of a sphere is (6.3±0.1) cm. The percentage error in its volume is
Answer» The radius of a sphere is $(6.3 \pm 0.1) cm$ . The percentage error in its volume is

Discussion

34.	A wire of resistance of 20Ω is bent to form a closed square. What is the resistance across the diagonal of the square?
Answer» A wire of resistance of 20 $Ω$ is bent to form a closed square. What is the resistance across the diagonal of the square?

Discussion

35.	A block of mass m=20 kg is kept at a distance R=1m from the central axis of rotation of a round turn table (a table whose surface can rotate about the central axis). Table starts from rest and rotates with constant angular acceleration, α=3 rad/sec2. The friction coefficient between the block and the table is μ=0.5. At time t=x30 from the starting of the motion (i.e. t=0), the block is just about to slip. The value of x is (g=10ms−2)
Answer» A block of mass $m = 20 k g$ is kept at a distance $R = 1 m$ from the central axis of rotation of a round turn table (a table whose surface can rotate about the central axis). Table starts from rest and rotates with constant angular acceleration, $α = 3 r a d / s e c^{2}$ . The friction coefficient between the block and the table is $μ = 0.5$ . At time $t = \frac{x}{30}$ from the starting of the motion (i.e. $t = 0$ ), the block is just about to slip. The value of $x$ is ( $g = 10 m s^{- 2}$ )

Discussion

36.	How many significant figures are there in this =5 × 5.364
Answer» How many significant figures are there in this =5 × 5.364

36.

How many significant figures are there in this =5 × 5.364

Answer»

How many significant figures are there in this

=5 × 5.364

Discussion

37.	When two identical batteries of internal resistance 1Ω each are connected in series across a resistor R, the rate of heat produced in R is J1. When the same batteries are connected in parallel across R, the rate is J2. If J1 = 2.25 J2, then the value of R (In Ω ) is ?
Answer» When two identical batteries of internal resistance 1 $Ω$ each are connected in series across a resistor R, the rate of heat produced in R is $J_{1}$ . When the same batteries are connected in parallel across R, the rate is $J_{2}$ . If $J_{1}$ = 2.25 $J_{2}$ , then the value of R (In $Ω$ ) is ?

Discussion

38.	A thin glass lens (refractive index = 1.5) has an optical power of 5D in air. Its optical power in a liquid of refractive index 1.6 is
Answer» A thin glass lens (refractive index = 1.5) has an optical power of 5D in air. Its optical power in a liquid of refractive index 1.6 is

Discussion

39.	At a distance L from a uniformly long wire, a charged particle is thrown radially outwards with a velocity u in the direction perpendicular to the wire. When the particle reaches a distance 2L from the wire, its speed is found to be u√2 . The magnitude of the velocity when it is at a distance of 16L away from the wire is pu, where p is (ignore gravity)
Answer» At a distance $L$ from a uniformly long wire, a charged particle is thrown radially outwards with a velocity $u$ in the direction perpendicular to the wire. When the particle reaches a distance $2 L$ from the wire, its speed is found to be $u \sqrt{2}$ . The magnitude of the velocity when it is at a distance of $16 L$ away from the wire is $p u$ , where $p$ is (ignore gravity)

Discussion

40.	An observer looks at a distant tree of height 10m with a telescope of magnifying power of 20. To the observer the tree appears:
Answer» An observer looks at a distant tree of height 10m with a telescope of magnifying power of 20. To the observer the tree appears:

Discussion

41.	A block of mass m is moving down with constant velocity along an inclined plane of inclination θ. What is the work done by an external force (applied parallel to the inclined plane) in pulling the block up the inclined plane through a height ′h′ with constant velocity?
Answer» A block of mass $m$ is moving down with constant velocity along an inclined plane of inclination $θ$ . What is the work done by an external force (applied parallel to the inclined plane) in pulling the block up the inclined plane through a height $^{'} h^{'}$ with constant velocity?

Discussion

42.	In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
Answer» In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of

Discussion

43.	What is the ratio of readings by spring balances A & D
Answer» What is the ratio of readings by spring balances $A$ & $D$

Discussion

44.	Two blocks of masses m and 2 m placed one over the other as shown in figure. The coefficient of friction between m and 2m is µ and between 2m and ground is μ3. If a horizontal force F is applied on upper block and T is tension developed in string then choose the incorrect alternative.
Answer» Two blocks of masses m and 2 m placed one over the other as shown in figure. The coefficient of friction between m and 2m is µ and between 2m and ground is $\frac{μ}{3}$ . If a horizontal force F is applied on upper block and T is tension developed in string then choose the incorrect alternative.

44.

Two blocks of masses m and 2 m placed one over the other as shown in figure. The coefficient of friction between m and 2m is µ and between 2m and ground is μ3. If a horizontal force F is applied on upper block and T is tension developed in string then choose the incorrect alternative.

Answer»

Two blocks of masses m and 2 m placed one over the other as shown in figure. The coefficient of friction between m and 2m is µ and between 2m and ground is $\frac{μ}{3}$ . If a horizontal force F is applied on upper block and T is tension developed in string then choose the incorrect alternative.

Discussion

45.	Two mutually perpendicular insulated long conducting wires carrying equal currents I, intersect at origin. Then the resultant magnetic induction at point P(2m,3m) will be
Answer» Two mutually perpendicular insulated long conducting wires carrying equal currents $I$ , intersect at origin. Then the resultant magnetic induction at point $P (2 m, 3 m)$ will be

Discussion

46.	A steel wire of length, mass and cross sectional area of 1 m, 0.1 kg and 10−6 m2 respectively is rigidly fixed at both ends. Now, if the temperature of the wire is lowered by 20∘C and transverse waves are setup by plucking the wire at 0.25 m from one end. Assuming that the wire vibrates with minimum number of loops possible, for such case the frequency of vibration in Hz is 11x. Then the value of x is . Write upto two digits after the decimal point. [αsteel=1.21×10−5 /∘C and Y=2.0×1011 N/m2 ]
Answer» A steel wire of length, mass and cross sectional area of 1 $m$ , 0.1 $k g$ and $10^{- 6} m^{2}$ respectively is rigidly fixed at both ends. Now, if the temperature of the wire is lowered by $20^{\circ} C$ and transverse waves are setup by plucking the wire at 0.25 $m$ from one end. Assuming that the wire vibrates with minimum number of loops possible, for such case the frequency of vibration in $H z$ is $11 x$ . Then the value of $x$ is . Write upto two digits after the decimal point. [ $α_{s t e e l} = 1.21 \times 10^{- 5} /^{\circ} C$ and $Y = 2.0 \times 10^{11} N / m^{2}$ ]

Discussion

47.	In a very long solenoid of radius R, if the magnetic field changes at the rate of dBdt, the induced emf for the triangular circuit ABC as shown in the figure is (AB=BC)
Answer» In a very long solenoid of radius $R$ , if the magnetic field changes at the rate of $\frac{d B}{d t}$ , the induced emf for the triangular circuit ABC as shown in the figure is (AB=BC)

Discussion

48.	A particle is projected with initial speed 10 m/s at an angle of 53∘ with horizontal. Then the time after which its speed becomes half of the initial speed.
Answer» A particle is projected with initial speed 10 m/s at an angle of $53^{\circ}$ with horizontal. Then the time after which its speed becomes half of the initial speed.

Discussion

49.	A bar of length L0=3.77 m is placed on two rigid supports as shown in the figure. As a result of rise in temperature by 32 ∘C , bar cracks at its centre and buckles upward as shown in the figure. The fixed distance between the supports is also L0=3.77 m and coefficient of linear expansion of the bar is 25×10−6/ ∘C. Find the rise x of centre of the bar.
Answer» A bar of length $L_{0} = 3.77 m$ is placed on two rigid supports as shown in the figure. As a result of rise in temperature by $32^{\circ} C$ , bar cracks at its centre and buckles upward as shown in the figure. The fixed distance between the supports is also $L_{0} = 3.77 m$ and coefficient of linear expansion of the bar is $25 \times 10^{- 6} /^{\circ} C$ . Find the rise $x$ of centre of the bar.

Discussion

50.	Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant, one particle is at its extreme position while the other is at its mean position. They move in the same direction. They will cross each other after a further time
Answer» Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant, one particle is at its extreme position while the other is at its mean position. They move in the same direction. They will cross each other after a further time

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A light bulb is rated at 125 W for a 250 V a.c., supply. Calculate the resistance of the bulb.

A body of mass 0.1 kg moving with a velocity of 10 m/s hits a spring (fixed at the other end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is

A solid body starts rotating about a stationary axis with an angular acceleration α = α0cos φ, φ is the angle of rotation from the initial position. Find the angular velocity of the body as a function of the angle φ.

(a) For a given AC, i=im sin ωt, show that the average power dissipated in a resistor R over a complete cycle is 12i2mR. (b) A light bulb is rated at 100W for a 220V AC supply. Calculate the resistance of the bulb.

The loss of weight of a solid when immersed in a liquid at 0∘C is W0 then the loss of weight W at t∘C is - where α and β are the cubical expansion coefficients of solid and liquid respectively.

Which retinal cells are involved in colour vision?

A parallel plate condenser with plate separation ‘d’ and plate area A is connected to a battery and charged to a potential V. Then the battery is disconnected and with insultated handles the plate separation is increased to 2d. Work done in the process will be?

Differentiate y=cosec xcotx w.r.t x

The time constant of a capacitor is 5sec. If the capacitance is C=100nF and it is charged from zero by a cell of EMF 10V through a resistor. What is the charge on it after 3 seconds?

In 2D plane , the equations of the partical's motion -- x= 5t2+2 , y= 2t2+5 ; Then, the motion path of the partical is --- a) parabola, b) circle, c) straight, d) hyperbola

A step up transformer operates on a 230V line and a load current of 2A. The ratio of the primray and secondary windings is 1 : 25. The current in the primary is

Two particles A and B, each having a charge Q, are placed a distance d apart where should a particle of charge q be placed on the perpendicular bisector of AB so that it experiences maximum force ? What is the magnitude of this maximum force?

Work done by a system under isothermal change from a volume V1 to V2 for a gas which obeys Vander Waal's equation (V−β n)(P+an2V)=nRT

Discuss the use pattern of energy consumption in India.

Which of the following may have coordinates of center of mass as (−a,−b), where a &amp; b are positive constants.

Which of the following figures represents damped harmonic motion?

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, ratio of the rates of cooling of A and B will be

Five identical cubes each of mass ‘m′ are on a straight line with two adjacent faces in contact on a horizontal surface as shown in the figure. Suppose the surface is frictionless and a constant force P is applied from left to right to the end face of A, then net force on each cube is

A long soleniod has 200 turns per cm and carries a current i. The magnetic field at its centre is 6.28×10−2 Weber/m2. Another long solenoid has 100 turns per cm and it carries a current i3 The value of the magnetic field at its centre is

When 1 mole of A(g) is introduced in a closed rigid 1 litre vessel maintained at constant temperature the following equilibria are established A(g)⇌B(g)+C(g):KC1 C(g)⇌D(g)+B(g):KC2 The pressure at equilibrium is twice the initial pressure. Calculate the value of KC2KC1 if [C]eq[B]eq=15.

The time period of a conical pendulum shown in figure is:

The spectrum of radiation 1.0×1014Hz is in the infrared region. The energy of one photon of this in joules will be

If heat is given to an ideal gas at constant pressure, then select the graph which best represents the variation of VT with temperature (T).

Strip of wood of mass M and length l is placed on a smooth horizontal surface. An insect of mass m starts at one end of the strip and walks to the other end in time t, moving with a constant speed. Then the speed of the strip as seen from the ground is

A small sphere of radius r falls from rest in a viscous liquid. Heat is produced due to friction between the liquid and the sphere. Choose the correct relation between rate of production of heat and the radius of the sphere, when terminal velocity is attained.

In the figure shown, the equivalent capacitance between ′A′ and ′B′ is:

The power factor of a circuit in which a box having unknown electrical devices connected in series with a resistor of resistance 3 Ω is 35. The reactance of the box is

The radius of a sphere is (6.3±0.1) cm. The percentage error in its volume is

A wire of resistance of 20Ω is bent to form a closed square. What is the resistance across the diagonal of the square?

How many significant figures are there in this =5 × 5.364

When two identical batteries of internal resistance 1Ω each are connected in series across a resistor R, the rate of heat produced in R is J1. When the same batteries are connected in parallel across R, the rate is J2. If J1 = 2.25 J2, then the value of R (In Ω ) is ?

A thin glass lens (refractive index = 1.5) has an optical power of 5D in air. Its optical power in a liquid of refractive index 1.6 is

An observer looks at a distant tree of height 10m with a telescope of magnifying power of 20. To the observer the tree appears:

A block of mass m is moving down with constant velocity along an inclined plane of inclination θ. What is the work done by an external force (applied parallel to the inclined plane) in pulling the block up the inclined plane through a height ′h′ with constant velocity?

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of

What is the ratio of readings by spring balances A &amp; D

Two blocks of masses m and 2 m placed one over the other as shown in figure. The coefficient of friction between m and 2m is µ and between 2m and ground is μ3. If a horizontal force F is applied on upper block and T is tension developed in string then choose the incorrect alternative.

Two mutually perpendicular insulated long conducting wires carrying equal currents I, intersect at origin. Then the resultant magnetic induction at point P(2m,3m) will be

In a very long solenoid of radius R, if the magnetic field changes at the rate of dBdt, the induced emf for the triangular circuit ABC as shown in the figure is (AB=BC)

A particle is projected with initial speed 10 m/s at an angle of 53∘ with horizontal. Then the time after which its speed becomes half of the initial speed.

Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant, one particle is at its extreme position while the other is at its mean position. They move in the same direction. They will cross each other after a further time

Which of the following may have coordinates of center of mass as (−a,−b), where a & b are positive constants.

What is the ratio of readings by spring balances A & D