50278 + Interview Questions in Physics Page 237 InterviewSolution

11801.	Energy stored in spring A=20 J, then energy stored in spring B is (under same extension of the spring)
Answer» Energy stored in spring $A = 20 J$ , then energy stored in spring $B$ is (under same extension of the spring)

Discussion

11802.	A bird is flying toward north with velocity 40 km/h and a train is moving with velocity 40 km/h towards east. What is the velocity of the bird noted by a man at rest in the train.
Answer» A bird is flying toward north with velocity 40 km/h and a train is moving with velocity 40 km/h towards east. What is the velocity of the bird noted by a man at rest in the train.

Discussion

11803.	A person wants to roll a solid non-conducting spherical ball of mass m and radius r on a surface whose coefficient of static friction is μ. He placed the ball on the surface wrapped with n turns of closely packed conducting coils of negligible mass at the diameter. By some arrangement he is able to pass a current i through the coils either in the clockwise direction or in the anti-clockwise direction. A constant horizontal magnetic field B is present throughout the space as shown in the figure. (Assume μ is large enough to help rolling motion) The angular velocity of the ball when it has rotated through an angle θ is (θ<180∘), is
Answer» A person wants to roll a solid non-conducting spherical ball of mass m and radius r on a surface whose coefficient of static friction is $μ$ . He placed the ball on the surface wrapped with n turns of closely packed conducting coils of negligible mass at the diameter. By some arrangement he is able to pass a current i through the coils either in the clockwise direction or in the anti-clockwise direction. A constant horizontal magnetic field B is present throughout the space as shown in the figure. (Assume $μ$ is large enough to help rolling motion) The angular velocity of the ball when it has rotated through an angle $θ$ is $(θ < 180^{\circ})$ , is

Discussion

11804.	In the following figure, the potential difference is shown on R,L & C. The emf of source in volt is
Answer» In the following figure, the potential difference is shown on $R, L$ & $C$ . The emf of source in $volt$ is

Discussion

11805.	The speed of sound in air at 20 degree celsius is about 343 metre per second.How?
Answer» The speed of sound in air at 20 degree celsius is about 343 metre per second.How?

Discussion

11806.	A man of mass M=50 kg stands at one end of a boat (of length L) which is floating in still water. The man walks to the other end of the boat. Length of the boat is L=10 m and mass M=20 kg. Then the distance moved by the boat relative to the ground is
Answer» A man of mass $M = 50 kg$ stands at one end of a boat (of length $L$ ) which is floating in still water. The man walks to the other end of the boat. Length of the boat is $L = 10 m$ and mass $M = 20 kg$ . Then the distance moved by the boat relative to the ground is

Discussion

11807.	An object AB of height 5 mm is kept to the left and on the axis of a converging lens of focal length 10 cm as shown in the figure. A plane mirror M is placed inclined at 45∘ to the lens axis at a distance of 10 cm to the right of the lens.(a) Find the size of the image of object AB.(b) Find the coordinates of the image of points A & B formed by this combination (take the centre of the lens as the origin and the lens axis as the positive x-axis).Consider the image after one refraction from lens and then one reflection from mirror only.
Answer» An object $A B$ of height $5 mm$ is kept to the left and on the axis of a converging lens of focal length $10 cm$ as shown in the figure. A plane mirror $M$ is placed inclined at $45^{\circ}$ to the lens axis at a distance of $10 cm$ to the right of the lens. $(a)$ Find the size of the image of object $A B$ . $(b)$ Find the coordinates of the image of points $A$ & $B$ formed by this combination (take the centre of the lens as the origin and the lens axis as the positive x-axis). Consider the image after one refraction from lens and then one reflection from mirror only.

Discussion

11808.	Two particles A and B of mass 1 kg and 2 kg respectively are kept 1 m apart and are released to move under mutual attraction. When speed of B is 3.6 cm/hour, what is the separation (in cm) between the particles. Take G=203×10−11 Nm2kg
Answer» Two particles $A$ and $B$ of mass $1 kg$ and $2 kg$ respectively are kept $1 m$ apart and are released to move under mutual attraction. When speed of $B$ is $3.6 cm/hour$ , what is the separation (in cm) between the particles. Take $G = \frac{20}{3} \times 10^{- 11} \frac{{Nm}^{2}}{kg}$

Discussion

11809.	Four thin uniform rods each of length L and mass M are jojned to form a square. The moment of inertia of square about an axis along its one diagonal is
Answer» Four thin uniform rods each of length L and mass M are jojned to form a square. The moment of inertia of square about an axis along its one diagonal is

Discussion

11810.	in YDSE a film ,refractive index 1.6 of thickness 0.01 mm is intriduced in the path of one of the two interfering beams . the centrel fringe moves to a position occupied by the 10th bright fringe earlier. the wavelength of wave
Answer» in YDSE a film ,refractive index 1.6 of thickness 0.01 mm is intriduced in the path of one of the two interfering beams . the centrel fringe moves to a position occupied by the 10th bright fringe earlier. the wavelength of wave

Discussion

11811.	A circular penstock of mild steel, 1.4 m in diameter, is fabricated in workshop with 12 mm thick plates. The plates are severed by 8 mm size fillet welds, provided on the inside and outside of the lapped ends as shown in figure. The safe internal pressure that can be allowed in the penstock will be N/mm2.γmw=1.25,FOS=1.5]2.02
Answer» A circular penstock of mild steel, 1.4 m in diameter, is fabricated in workshop with 12 mm thick plates. The plates are severed by 8 mm size fillet welds, provided on the inside and outside of the lapped ends as shown in figure. The safe internal pressure that can be allowed in the penstock will be $N / m m^{2}$ . $γ_{m w} = 1.25, F O S = 1.5]$ 2.02

11811.

A circular penstock of mild steel, 1.4 m in diameter, is fabricated in workshop with 12 mm thick plates. The plates are severed by 8 mm size fillet welds, provided on the inside and outside of the lapped ends as shown in figure. The safe internal pressure that can be allowed in the penstock will be N/mm2.γmw=1.25,FOS=1.5]2.02

Answer»

A circular penstock of mild steel, 1.4 m in diameter, is fabricated in workshop with 12 mm thick plates. The plates are severed by 8 mm size fillet welds, provided on the inside and outside of the lapped ends as shown in figure. The safe internal pressure that can be allowed in the penstock will be $N / m m^{2}$ .

$γ_{m w} = 1.25, F O S = 1.5]$

2.02

Discussion

11812.	The linear magnification produced by spherical mirrors is +3. Analyse this value and state the (i) type of mirror and (ii) Position of the object with respect to the pole of the mirror. Draw ray diagram to show the formation of image in this case.
Answer» The linear magnification produced by spherical mirrors is +3. Analyse this value and state the (i) type of mirror and (ii) Position of the object with respect to the pole of the mirror. Draw ray diagram to show the formation of image in this case.

Discussion

11813.	A rod PQ of length 1 m is placed on the frame CDEF. This setup is placed in a space where a uniform magnetic field →B, of magnitude 1 T exist. The rod moves with a constant velocity of 20 m/s. The power spent by external force to keep the rod moving with constant velocity is -Given, R=0.2 Ω and all other wires and rod have zero resistance.
Answer» A rod $P Q$ of length $1 m$ is placed on the frame $C D E F$ . This setup is placed in a space where a uniform magnetic field $\to B$ , of magnitude $1 T$ exist. The rod moves with a constant velocity of $20 m/s$ . The power spent by external force to keep the rod moving with constant velocity is - Given, $R = 0.2 Ω$ and all other wires and rod have zero resistance.

Discussion

11814.	A ball is thrown vertically upward with the speed of 40 m/s. If the dis†an ce travelled by the ball in 6 seconds is 50K meter then what is the value of K? (g=10 m/s^2 and neglect air friction
Answer» A ball is thrown vertically upward with the speed of 40 m/s. If the dis†an ce travelled by the ball in 6 seconds is 50K meter then what is the value of K? (g=10 m/s^2 and neglect air friction

Discussion

11815.	A parallel-plate capacitor of capacitance 5 μF is connected to a battery of emf 6 V. The separation between the plates is 2 mm. (a) Find the charge on the positive plate. (b) Find the electric field between the plates. (c) A dielectric slab of thickness 1 mm and dielectric constant 5 is inserted into the gap to occupy the lower half of it. Find the capacitance of the new combination (d) How much charge has flown through the battery after the slab is inserted ?
Answer» A parallel-plate capacitor of capacitance $5 μ F$ is connected to a battery of emf 6 V. The separation between the plates is 2 mm. (a) Find the charge on the positive plate. (b) Find the electric field between the plates. (c) A dielectric slab of thickness 1 mm and dielectric constant 5 is inserted into the gap to occupy the lower half of it. Find the capacitance of the new combination (d) How much charge has flown through the battery after the slab is inserted ?

Discussion

11816.	A particle is projected from ground with speed u such that the horizontal range is R and maximum height is H. The angular velocity of the particle about the point of projection, when it is at the highest point of its trajectory is:
Answer» A particle is projected from ground with speed $u$ such that the horizontal range is $R$ and maximum height is $H$ . The angular velocity of the particle about the point of projection, when it is at the highest point of its trajectory is:

Discussion

11817.	A mild steel specimen is under uniaxial tensile stress . Young's modulus and yield stress for mild steel are 2×105 MPa and 250 MPa respectively. The maximum amount of strain energy per unit volume that can be stored in this specimen without permanent set is
Answer» A mild steel specimen is under uniaxial tensile stress . Young's modulus and yield stress for mild steel are $2 \times 10^{5} M P a$ and $250 M P a$ respectively. The maximum amount of strain energy per unit volume that can be stored in this specimen without permanent set is

Discussion

11818.	a string is used to pull a block of mass m vertically up by a dis†an ce h at a cons†an t acceleration g/3 The work done by the tension in the tension in the string is
Answer» a string is used to pull a block of mass m vertically up by a dis†an ce h at a cons†an t acceleration g/3 The work done by the tension in the tension in the string is

Discussion

11819.	9. ) The current in the primary circuit of a potentiometeris 0.2 A. The specific resistance and cross-sectionof the potentiometer wire are 4 x 10-7 ohm m and8 x 10- m2 respectively. The potential gradient willbe equal to(1) 0.2 V/m(2) 1 V/m(4) 0.1 V/m(3) 0.5 V/m
Answer» 9. ) The current in the primary circuit of a potentiometeris 0.2 A. The specific resistance and cross-sectionof the potentiometer wire are 4 x 10-7 ohm m and8 x 10- m2 respectively. The potential gradient willbe equal to(1) 0.2 V/m(2) 1 V/m(4) 0.1 V/m(3) 0.5 V/m

Discussion

11820.	In the relation : dydt=2ω sin(ωt+ϕ), the dimensional formula for (ωt+ϕ) is
Answer» In the relation : $\frac{d y}{d t} = 2 ω s i n (ω t + ϕ)$ , the dimensional formula for $(ω t + ϕ)$ is

Discussion

11821.	The laws of gravitation give the gravitational force between____.
Answer» The laws of gravitation give the gravitational force between____.

Discussion

11822.	Two forces, with equal magnitude F, act on a body and the magnitude of the resultant force is F3. The angle between the two forces is
Answer» Two forces, with equal magnitude $F$ , act on a body and the magnitude of the resultant force is $\frac{F}{3}$ . The angle between the two forces is

Discussion

11823.	A body starts from rest, and moves with an acceleration of 1 ms−2. The displacement (in m) of the body in 5 seconds is
Answer» A body starts from rest, and moves with an acceleration of $1 m s^{- 2}$ . The displacement (in $m$ ) of the body in $5$ seconds is

Discussion

11824.	A uniform rod ABC of mass M is placed vertically on a rough horizontal surface. The coefficient of kinetic friction between the rod and the surface is μ. A force F(>μmg) is applied on the rod at point B at distance l/3 below centre of the rod as shown in figure. The initial acceleration of point A is
Answer» A uniform rod $A B C$ of mass $M$ is placed vertically on a rough horizontal surface. The coefficient of kinetic friction between the rod and the surface is $μ$ . A force $F (> μ m g)$ is applied on the rod at point $B$ at distance $l / 3$ below centre of the rod as shown in figure. The initial acceleration of point $A$ is

Discussion

11825.	Two blocks are connected by a spring, the combination is suspended at rest, from a string attached to the ceiling, as shown in the figure, the string breaks suddenly. Immediately after the string breaks, what is the initial downward acceleration of the upper block of mass 2m?
Answer» Two blocks are connected by a spring, the combination is suspended at rest, from a string attached to the ceiling, as shown in the figure, the string breaks suddenly. Immediately after the string breaks, what is the initial downward acceleration of the upper block of mass 2m?

Discussion

11826.	A resistor of 100 ohm, pure inductance coil of 0.5H and capacitor are in series in a circuit containing an AC source of 200V 50H . In the circuit , current is ahead of voltage by 30degree. Find the value of capacitance.why should we take Xc-Xl itself?
Answer» A resistor of 100 ohm, pure inductance coil of 0.5H and capacitor are in series in a circuit containing an AC source of 200V 50H . In the circuit , current is ahead of voltage by 30degree. Find the value of capacitance. why should we take Xc-Xl itself?

Discussion

11827.	35. An open flask contqins air at 27^° c to what temp it must be heated to expel one fourth of the air ?
Answer» 35. An open flask contqins air at 27^° c to what temp it must be heated to expel one fourth of the air ?

Discussion

11828.	76.Two soap Bubbles having ready 6 centimetre and 8 centimetre in vacuum coalesce under isothermal conditions. The radius of the new bubble is
Answer» 76.Two soap Bubbles having ready 6 centimetre and 8 centimetre in vacuum coalesce under isothermal conditions. The radius of the new bubble is

Discussion

11829.	A capacitor of capacitance 100 μF is connected across a battery of e.m.f 6.0 V through a resistance of 20 kΩ for 4.0 s. The battery is then replaced by a thick wire, what will be the charge on the capacitor 4.0 s after the battery is disconnected ?
Answer» A capacitor of capacitance $100 μ F$ is connected across a battery of e.m.f $6.0 V$ through a resistance of $20 k Ω$ for $4.0 s$ . The battery is then replaced by a thick wire, what will be the charge on the capacitor $4.0 s$ after the battery is disconnected ?

Discussion

11830.	46.A ball weighing 10 gram hits a hard surface vertically with a speed of 5 metre per second and rebounds with the same speed the ball remain in contact with the surface for 0.01 second the average force exerted by the surface on the ball is
Answer» 46.A ball weighing 10 gram hits a hard surface vertically with a speed of 5 metre per second and rebounds with the same speed the ball remain in contact with the surface for 0.01 second the average force exerted by the surface on the ball is

Discussion

11831.	A man lifts a luggage of 10kg from the ground and puts it on his head 1.7m above the ground. Calculate work done by him and gravity on the luggage respectively. Take acceleration due to gravity=10ms−2.
Answer» A man lifts a luggage of $10 k g$ from the ground and puts it on his head $1.7 m$ above the ground. Calculate work done by him and gravity on the luggage respectively. Take acceleration due to gravity $= 10 m s^{- 2}$ .

Discussion

11832.	One end of a uniform wire of length L and of weight W is attached rigidly to a point in the ceiling and a weight W1 is suspended from its lower end. If S is the area of cross – section of the wire, the stress in the wire at a height 3L/4 from its lower end is
Answer» One end of a uniform wire of length L and of weight W is attached rigidly to a point in the ceiling and a weight $W_{1}$ is suspended from its lower end. If S is the area of cross – section of the wire, the stress in the wire at a height 3L/4 from its lower end is

Discussion

11833.	From a disc of radius R and mass M Two circular holes each of diameter R whose rim passes through the centre is cut the moment of inertia of the remaining part of the disc about an axis passing through center of original disc and perpendicular to the plane of the disc is( distance between center of holes is R )
Answer» From a disc of radius R and mass M Two circular holes each of diameter R whose rim passes through the centre is cut the moment of inertia of the remaining part of the disc about an axis passing through center of original disc and perpendicular to the plane of the disc is( distance between center of holes is R )

Discussion

11834.	The ear-ring of a lady shown in figure (12-E18) has a 3 cm long light suspension wire. (a) Find the time period of small oscillations if the lady is standing on the ground. (b) The lady now sits in a merry-go-round moving at 4 m s−1 in a circle of radius 2 m. Find the time period of small oscillations of the ear-ring.
Answer» The ear-ring of a lady shown in figure (12-E18) has a 3 cm long light suspension wire. (a) Find the time period of small oscillations if the lady is standing on the ground. (b) The lady now sits in a merry-go-round moving at $4 m s^{- 1}$ in a circle of radius 2 m. Find the time period of small oscillations of the ear-ring.

11834.

The ear-ring of a lady shown in figure (12-E18) has a 3 cm long light suspension wire. (a) Find the time period of small oscillations if the lady is standing on the ground. (b) The lady now sits in a merry-go-round moving at 4 m s−1 in a circle of radius 2 m. Find the time period of small oscillations of the ear-ring.

Answer»

The ear-ring of a lady shown in figure (12-E18) has a 3 cm long light suspension wire. (a) Find the time period of small oscillations if the lady is standing on the ground. (b) The lady now sits in a merry-go-round moving at $4 m s^{- 1}$ in a circle of radius 2 m. Find the time period of small oscillations of the ear-ring.

Discussion

11835.	Frequency of a wave does notchange with change in themediumFrequency is the number ofoscillations performed per unittime.Suppose in medium A, thenumber of oscillations is 10times and the time taken is is 2secondsTherefore frequency should be10/2 that is 5 HzNow since the medium changesin case of B that is in medium Bthe number of oscillations is thesame that is 10 times but thetime taken to perform 10 oscillations is 5 seconds.Thereforefrequency should be 2 Hz.Then how does it differ?
Answer» Frequency of a wave does notchange with change in themediumFrequency is the number ofoscillations performed per unittime.Suppose in medium A, thenumber of oscillations is 10times and the time taken is is 2secondsTherefore frequency should be10/2 that is 5 HzNow since the medium changesin case of B that is in medium Bthe number of oscillations is thesame that is 10 times but thetime taken to perform 10 oscillations is 5 seconds.Thereforefrequency should be 2 Hz.Then how does it differ?

Discussion

11836.	Air (assume it to be a mixture of N2 and O2) at pressure P and volume V is expanded adiabatically. The volume increases by 5%. What will be the correct relation between initial and final pressure(P1).
Answer» Air (assume it to be a mixture of $N_{2}$ and $O_{2}$ ) at pressure $P$ and volume $V$ is expanded adiabatically. The volume increases by $5 %$ . What will be the correct relation between initial and final pressure $(P_{1})$ .

Discussion

11837.	Is there a limation on the semivertical angel of a conical pendulum?
Answer» Is there a limation on the semivertical angel of a conical pendulum?

Discussion

11838.	Consider the circuit shown in the figure below:The diode 'D' can be modeled as a battery of voltage Vγ in series with a resistor ′r′f when biased in forward direction. If the value of resistance R=1 kΩ, then the value of resistance rf is equal to
Answer» Consider the circuit shown in the figure below: The diode 'D' can be modeled as a battery of voltage $V_{γ}$ in series with a resistor $^{'} r_{f}^{'}$ when biased in forward direction. If the value of resistance $R = 1 k Ω$ , then the value of resistance $r_{f}$ is equal to

Discussion

11839.	For a magnetising field of intensity 2×103 Am−1, aluminium at 280 K acquires intensity of magnetisation of 4.8×10−2 Am−1. If the temperature of the metal is raised to 320 K, what will be the intensity of magnetisation ?
Answer» For a magnetising field of intensity $2 \times 10^{3} {Am}^{- 1}$ , aluminium at $280 K$ acquires intensity of magnetisation of $4.8 \times 10^{- 2} {Am}^{- 1} .$ If the temperature of the metal is raised to $320 K$ , what will be the intensity of magnetisation ?

Discussion

11840.	A ball projected from ground vertically upward is at time t1and t2. The speed of projection of ball is ( neglecte the effect of airresistance)
Answer» A ball projected from ground vertically upward is at time t1and t2. The speed of projection of ball is ( neglecte the effect of airresistance)

Discussion

11841.	A ring has radius 30cm and a charge of 2nc the electric potential on the axis of the ring at a distance of 40cm from the center will we
Answer» A ring has radius 30cm and a charge of 2nc the electric potential on the axis of the ring at a distance of 40cm from the center will we

Discussion

11842.	If the rate of change in the circumference of a circle is 0.5 cm/sec, then the rate of change in its area, when the circumference is 10π cm, is equal to(in sq.cm/sec)
Answer» If the rate of change in the circumference of a circle is $0.5 cm/sec$ , then the rate of change in its area, when the circumference is $10 π cm,$ is equal to(in $sq.cm/sec$ )

Discussion

11843.	Find VA−VB in steady state
Answer» Find $V_{A} - V_{B}$ in steady state

Discussion

11844.	A block of mass m is connected to a spring of spring constant K as shown in figure. The frame in which block is placed is given an acceleration 'a' towards left. Neglect friction between block and frame walls. The maximum velocity of the block relative to frame is
Answer» A block of mass m is connected to a spring of spring constant K as shown in figure. The frame in which block is placed is given an acceleration 'a' towards left. Neglect friction between block and frame walls. The maximum velocity of the block relative to frame is

11844.

A block of mass m is connected to a spring of spring constant K as shown in figure. The frame in which block is placed is given an acceleration 'a' towards left. Neglect friction between block and frame walls. The maximum velocity of the block relative to frame is

Answer»

A block of mass m is connected to a spring of spring constant K as shown in figure. The frame in which block is placed is given an acceleration 'a' towards left. Neglect friction between block and frame walls. The maximum velocity of the block relative to frame is

Discussion

11845.	A conducting rod of length l=0.5 m is hinged at point O. It is free to rotate in a vertical plane. There exists a uniform magnetic field B=2 T as shown in the figure. The rod is released freely. When the rod makes an angle of θ=37∘ from the released position then the potential difference between the ends of the rod is :
Answer» A conducting rod of length $l = 0.5 m$ is hinged at point $O$ . It is free to rotate in a vertical plane. There exists a uniform magnetic field $B = 2 T$ as shown in the figure. The rod is released freely. When the rod makes an angle of $θ = 37^{\circ}$ from the released position then the potential difference between the ends of the rod is :

Discussion

11846.	27. A vertical hanging bar of length l & mass m per unit lenght carries a load of Mass M at lower end, its upper end is clamped to a rigit support. The tensile stress a distance x from support is ( A= area of cross section of bar) 1) Mg + mg (1-x)/A 2) Mg/A 3) Mg + mgl/A 4) (M+m)gx/Al
Answer» 27. A vertical hanging bar of length l & mass m per unit lenght carries a load of Mass M at lower end, its upper end is clamped to a rigit support. The tensile stress a distance x from support is ( A= area of cross section of bar) 1) Mg + mg (1-x)/A 2) Mg/A 3) Mg + mgl/A 4) (M+m)gx/Al

Discussion

11847.	Convince yourself that parts (a), (b) and (c) of figure (31-E13) are identical. Find the capacitance between the points A and B of the assembly.
Answer» Convince yourself that parts (a), (b) and (c) of figure (31-E13) are identical. Find the capacitance between the points A and B of the assembly.

11847.

Convince yourself that parts (a), (b) and (c) of figure (31-E13) are identical. Find the capacitance between the points A and B of the assembly.

Answer»

Convince yourself that parts (a), (b) and (c) of figure (31-E13) are identical. Find the capacitance between the points A and B of the assembly.

Discussion

11848.	Two identical capacitors have the same capaci†an ce C.One of them is charged to potential V_{1 }and other to V_2.The negative ends of the capacitots are connected together.When the positive ends are also connected, what is the decrease in energy of the combined system
Answer» Two identical capacitors have the same capaci†an ce C.One of them is charged to potential V_{1 }and other to V_2.The negative ends of the capacitots are connected together.When the positive ends are also connected, what is the decrease in energy of the combined system

Discussion

11849.	A metallic sphere is charged so that surface charge density is sigma. The mechanical stress (pressure) experienced by the surface is equal to (in terms of sigma and epsilon)
Answer» A metallic sphere is charged so that surface charge density is sigma. The mechanical stress (pressure) experienced by the surface is equal to (in terms of sigma and epsilon)

Discussion

11850.	Four equal charges Q are placed at the vertex of a square of side length a. Find the force experienced by a charge q placed at the midpoint of a side as shown in figure.
Answer» Four equal charges Q are placed at the vertex of a square of side length a. Find the force experienced by a charge q placed at the midpoint of a side as shown in figure.

Discussion

Explore topic-wise InterviewSolutions in .

Energy stored in spring A=20 J, then energy stored in spring B is (under same extension of the spring)

A bird is flying toward north with velocity 40 km/h and a train is moving with velocity 40 km/h towards east. What is the velocity of the bird noted by a man at rest in the train.

In the following figure, the potential difference is shown on R,L &amp; C. The emf of source in volt is

The speed of sound in air at 20 degree celsius is about 343 metre per second.How?

A man of mass M=50 kg stands at one end of a boat (of length L) which is floating in still water. The man walks to the other end of the boat. Length of the boat is L=10 m and mass M=20 kg. Then the distance moved by the boat relative to the ground is

Two particles A and B of mass 1 kg and 2 kg respectively are kept 1 m apart and are released to move under mutual attraction. When speed of B is 3.6 cm/hour, what is the separation (in cm) between the particles. Take G=203×10−11 Nm2kg

Four thin uniform rods each of length L and mass M are jojned to form a square. The moment of inertia of square about an axis along its one diagonal is

in YDSE a film ,refractive index 1.6 of thickness 0.01 mm is intriduced in the path of one of the two interfering beams . the centrel fringe moves to a position occupied by the 10th bright fringe earlier. the wavelength of wave

The linear magnification produced by spherical mirrors is +3. Analyse this value and state the (i) type of mirror and (ii) Position of the object with respect to the pole of the mirror. Draw ray diagram to show the formation of image in this case.

A ball is thrown vertically upward with the speed of 40 m/s. If the dis†an ce travelled by the ball in 6 seconds is 50K meter then what is the value of K? (g=10 m/s^2 and neglect air friction

A particle is projected from ground with speed u such that the horizontal range is R and maximum height is H. The angular velocity of the particle about the point of projection, when it is at the highest point of its trajectory is:

A mild steel specimen is under uniaxial tensile stress . Young's modulus and yield stress for mild steel are 2×105 MPa and 250 MPa respectively. The maximum amount of strain energy per unit volume that can be stored in this specimen without permanent set is

a string is used to pull a block of mass m vertically up by a dis†an ce h at a cons†an t acceleration g/3 The work done by the tension in the tension in the string is

9. ) The current in the primary circuit of a potentiometeris 0.2 A. The specific resistance and cross-sectionof the potentiometer wire are 4 x 10-7 ohm m and8 x 10- m2 respectively. The potential gradient willbe equal to(1) 0.2 V/m(2) 1 V/m(4) 0.1 V/m(3) 0.5 V/m

In the relation : dydt=2ω sin(ωt+ϕ), the dimensional formula for (ωt+ϕ) is

The laws of gravitation give the gravitational force between____.

Two forces, with equal magnitude F, act on a body and the magnitude of the resultant force is F3. The angle between the two forces is

A body starts from rest, and moves with an acceleration of 1 ms−2. The displacement (in m) of the body in 5 seconds is

Two blocks are connected by a spring, the combination is suspended at rest, from a string attached to the ceiling, as shown in the figure, the string breaks suddenly. Immediately after the string breaks, what is the initial downward acceleration of the upper block of mass 2m?

A resistor of 100 ohm, pure inductance coil of 0.5H and capacitor are in series in a circuit containing an AC source of 200V 50H . In the circuit , current is ahead of voltage by 30degree. Find the value of capacitance.why should we take Xc-Xl itself?

35. An open flask contqins air at 27^° c to what temp it must be heated to expel one fourth of the air ?

76.Two soap Bubbles having ready 6 centimetre and 8 centimetre in vacuum coalesce under isothermal conditions. The radius of the new bubble is

A capacitor of capacitance 100 μF is connected across a battery of e.m.f 6.0 V through a resistance of 20 kΩ for 4.0 s. The battery is then replaced by a thick wire, what will be the charge on the capacitor 4.0 s after the battery is disconnected ?

46.A ball weighing 10 gram hits a hard surface vertically with a speed of 5 metre per second and rebounds with the same speed the ball remain in contact with the surface for 0.01 second the average force exerted by the surface on the ball is

A man lifts a luggage of 10kg from the ground and puts it on his head 1.7m above the ground. Calculate work done by him and gravity on the luggage respectively. Take acceleration due to gravity=10ms−2.

One end of a uniform wire of length L and of weight W is attached rigidly to a point in the ceiling and a weight W1 is suspended from its lower end. If S is the area of cross – section of the wire, the stress in the wire at a height 3L/4 from its lower end is

Air (assume it to be a mixture of N2 and O2) at pressure P and volume V is expanded adiabatically. The volume increases by 5%. What will be the correct relation between initial and final pressure(P1).

Is there a limation on the semivertical angel of a conical pendulum?

Consider the circuit shown in the figure below:The diode 'D' can be modeled as a battery of voltage Vγ in series with a resistor ′r′f when biased in forward direction. If the value of resistance R=1 kΩ, then the value of resistance rf is equal to

For a magnetising field of intensity 2×103 Am−1, aluminium at 280 K acquires intensity of magnetisation of 4.8×10−2 Am−1. If the temperature of the metal is raised to 320 K, what will be the intensity of magnetisation ?

A ball projected from ground vertically upward is at time t1and t2. The speed of projection of ball is ( neglecte the effect of airresistance)

A ring has radius 30cm and a charge of 2nc the electric potential on the axis of the ring at a distance of 40cm from the center will we

If the rate of change in the circumference of a circle is 0.5 cm/sec, then the rate of change in its area, when the circumference is 10π cm, is equal to(in sq.cm/sec)

Find VA−VB in steady state

A block of mass m is connected to a spring of spring constant K as shown in figure. The frame in which block is placed is given an acceleration 'a' towards left. Neglect friction between block and frame walls. The maximum velocity of the block relative to frame is

27. A vertical hanging bar of length l & mass m per unit lenght carries a load of Mass M at lower end, its upper end is clamped to a rigit support. The tensile stress a distance x from support is ( A= area of cross section of bar) 1) Mg + mg (1-x)/A 2) Mg/A 3) Mg + mgl/A 4) (M+m)gx/Al

Convince yourself that parts (a), (b) and (c) of figure (31-E13) are identical. Find the capacitance between the points A and B of the assembly.

Two identical capacitors have the same capaci†an ce C.One of them is charged to potential V_{1 }and other to V_2.The negative ends of the capacitots are connected together.When the positive ends are also connected, what is the decrease in energy of the combined system

A metallic sphere is charged so that surface charge density is sigma. The mechanical stress (pressure) experienced by the surface is equal to (in terms of sigma and epsilon)

Four equal charges Q are placed at the vertex of a square of side length a. Find the force experienced by a charge q placed at the midpoint of a side as shown in figure.

In the following figure, the potential difference is shown on R,L & C. The emf of source in volt is