50278 + Interview Questions in Physics Page 158 InterviewSolution

7851.	41.Two slabs A and B of different materials but of the same thickness are joined end to end to form a composite slab.Thermal conductivities of A and B are K1 and K2 are respectively.A steady temperature difference of 12 degree celcious is maintained across the composite slab.If K1=K2/2 the temperature difference across the slab A is
Answer» 41.Two slabs A and B of different materials but of the same thickness are joined end to end to form a composite slab.Thermal conductivities of A and B are K1 and K2 are respectively.A steady temperature difference of 12 degree celcious is maintained across the composite slab.If K1=K2/2 the temperature difference across the slab A is

Discussion

7852.	A small sphere falls from rest in a liquid. Due to viscosity heat is produced. Find the relation between the rate of production of heat and the radius of the sphere at terminal velocity.
Answer» A small sphere falls from rest in a liquid. Due to viscosity heat is produced. Find the relation between the rate of production of heat and the radius of the sphere at terminal velocity.

Discussion

7853.	8 In which of the following is the radius of the first orbit minimum 1 H-Atom 2 A tritium Atom 3 tiply ionized beryllium 4 double ionized helium
Answer» 8 In which of the following is the radius of the first orbit minimum 1 H-Atom 2 A tritium Atom 3 tiply ionized beryllium 4 double ionized helium

Discussion

7854.	White light is incident normally on a glass plate of thickness 0.50×10−6 m and index of refraction 1.50 . Which wavelengths in the visible region 400 nm−700 nm are strongly reflected by the plate?
Answer» White light is incident normally on a glass plate of thickness $0.50 \times 10^{- 6} m$ and index of refraction $1.50$ . Which wavelengths in the visible region $400 n m - 700 n m$ are strongly reflected by the plate?

Discussion

7855.	If two cars A and B start moving from the same point simultaneously have their positions varying with time t as and. Velocity of A w.r.t B, if their accelerations are equal, will be
Answer» If two cars A and B start moving from the same point simultaneously have their positions varying with time t as and. Velocity of A w.r.t B, if their accelerations are equal, will be

Discussion

7856.	The wavelength λ of Kβ X-Ray is given by:
Answer» The wavelength $λ$ of $K_{β}$ X-Ray is given by:

Discussion

7857.	what is the formula for electromagnetic force ? as well as what is the difference between electromagnetic forces and electrostatic forces??
Answer» what is the formula for electromagnetic force ? as well as what is the difference between electromagnetic forces and electrostatic forces??

Discussion

7858.	Does angular velocity depend on r? how and why?
Answer» Does angular velocity depend on r? how and why?

Discussion

7859.	Find the change in internal energy of 3 mol of helium gas when its temperature is increased by 2 K.
Answer» Find the change in internal energy of $3 mol$ of helium gas when its temperature is increased by $2 K$ .

Discussion

7860.	A boy of mass M is applying a horizontal force to slide a box of mass M' on a rough horizontal surface. The coefficient of friction between the shoes of the boy and the floor is μ and that between the box and the floor is μ'. In which of the following cases it is certainly not possible to slide the box given the boy is not slipping
Answer» A boy of mass M is applying a horizontal force to slide a box of mass M' on a rough horizontal surface. The coefficient of friction between the shoes of the boy and the floor is μ and that between the box and the floor is μ'. In which of the following cases it is certainly not possible to slide the box given the boy is not slipping

Discussion

7861.	A simple microscope consists of a concave lens of power −10 D and a convex lens of power +20 D in contact. If the image is formed at infinity, then the magnifying power is x2 , the value of x is : (Take the least distance of distinct vision as D=25 cm)
Answer» A simple microscope consists of a concave lens of power $- 10 D$ and a convex lens of power $+ 20 D$ in contact. If the image is formed at infinity, then the magnifying power is $\frac{x}{2}$ , the value of $x$ is : (Take the least distance of distinct vision as $D = 25$ cm)

Discussion

7862.	If V = 1 litre, 10 mole of H2 and 10 mole of N2 gas are mixed at temperature 26 oC then calculate pressure of the gas:
Answer» If V = 1 litre, 10 mole of $H_{2}$ and 10 mole of $N_{2}$ gas are mixed at temperature $26^{o} C$ then calculate pressure of the gas:

Discussion

7863.	___ consumes 80% less power as compared to ordinary bulbs.
Answer» ___ consumes 80% less power as compared to ordinary bulbs.

Discussion

7864.	An open rectangular tank 5m × 4m × 3mhigh containing water upto a height of 2m is accelerated horizontally along the larger side. If the acceleration is increased by 20%, the percenatage of water spilt over after increasing the acceleration is
Answer» An open rectangular tank 5m × 4m × 3m high containing water upto a height of 2m is accelerated horizontally along the larger side. If the acceleration is increased by 20%, the percenatage of water spilt over after increasing the acceleration is

Discussion

7865.	A particle of mass m is moving with a constant velocity v parallel to the x− axis as shown in the figure. Its angular momentum (magnitude) about origin O is
Answer» A particle of mass $m$ is moving with a constant velocity $v$ parallel to the $x -$ axis as shown in the figure. Its angular momentum (magnitude) about origin $O$ is

Discussion

7866.	What is unification of forces?
Answer» What is unification of forces?

Discussion

7867.	The displacement components at a point in a body for co-ordinate directions x,y & z are u,v and w respectively. Ifu=3x+2y+6zv=x2+3y+2zw=6y+z2The magnitude of shearing strain γxz is
Answer» The displacement components at a point in a body for co-ordinate directions $x, y$ & $z$ are $u, v$ and $w$ respectively. If $u = 3 x + 2 y + 6 z$ $v = x^{2} + 3 y + 2 z$ $w = 6 y + z^{2}$ The magnitude of shearing strain $γ_{x z}$ is

Discussion

7868.	ntQ: True/Falsen ntn ntA). In photoelectric emission process the maximum energy of the photoelectron increases with increasing intensity of the incident light. (Year 1986, 3 mark)n ntB). The kinetic energy of photoelectrons emitted by a photosensitive surface depends on the intensity of the incident radiation. (Year 1981,2 mark)n
Answer» ntQ: True/Falsen ntn ntA). In photoelectric emission process the maximum energy of the photoelectron increases with increasing intensity of the incident light. (Year 1986, 3 mark)n ntB). The kinetic energy of photoelectrons emitted by a photosensitive surface depends on the intensity of the incident radiation. (Year 1981,2 mark)n

Discussion

7869.	Two cities A and B are connected by a regular bus service with buses plying in either direction every T seconds . The speed of each bus is uniform and equal to Vb. A cyclist cycles from A to B with a uniform speed of Vc. A bus goes past the cyclist in T1 second in the direction A to B and every T2 second in the direction B to A. Then
Answer» Two cities $A$ and $B$ are connected by a regular bus service with buses plying in either direction every $T$ seconds . The speed of each bus is uniform and equal to $V_{b}$ . A cyclist cycles from $A$ to $B$ with a uniform speed of $V_{c}$ . A bus goes past the cyclist in $T_{1}$ second in the direction $A$ to $B$ and every $T_{2}$ second in the direction $B$ to $A$ . Then

Discussion

7870.	a gaseous compound of the density of 2.5 kg per metre cube at 2 ATM pressure and 546k .find the molecular formula of the compound?
Answer» a gaseous compound of the density of 2.5 kg per metre cube at 2 ATM pressure and 546k . find the molecular formula of the compound?

Discussion

7871.	The half-life of a radioactive substance is 20 min. The approximate time interval (t2−t1) between the time t2 when 23 of it had decayed and time t1 when 13 of it had decayed (in min) is (integer only)
Answer» The half-life of a radioactive substance is $20 min .$ The approximate time interval $(t_{2} - t_{1})$ between the time $t_{2}$ when $\frac{2}{3}$ of it had decayed and time $t_{1}$ when $\frac{1}{3}$ of it had decayed (in $min)$ is (integer only)

Discussion

7872.	Which of the following graphs correctly represents the variation of 1v versus 1u for a concave mirror?[v = image distance, u = object distance]
Answer» Which of the following graphs correctly represents the variation of $\frac{1}{v}$ versus $\frac{1}{u}$ for a concave mirror? [ $v$ = image distance, $u$ = object distance]

Discussion

7873.	17. Draw the intensity pattern for single slit diffraction and double slit interference. Hence, state two differences between interference and diffraction patterns
Answer» 17. Draw the intensity pattern for single slit diffraction and double slit interference. Hence, state two differences between interference and diffraction patterns

Discussion

7874.	Four squares plates A, B, C and D having densities σ1, σ2, σ3 and σ4 are kept as shown in figure. If σ1=0.5σ2; σ2=2σ3; σ3=σ44, then location of centre of mass of the system is given by
Answer» Four squares plates $A, B, C$ and $D$ having densities $σ_{1}, σ_{2}, σ_{3}$ and $σ_{4}$ are kept as shown in figure. If $σ_{1} = 0.5 σ_{2}; σ_{2} = 2 σ_{3}; σ_{3} = \frac{σ_{4}}{4}$ , then location of centre of mass of the system is given by

Discussion

7875.	At a place, the earth's horizontal component of magnetic field is 0.36×10−4 weber/m2. If the angle of dip at that place is 60∘, then the vertical component of earth's magnetic field at that place in weber/m2 will be approximately
Answer» At a place, the earth's horizontal component of magnetic field is $0.36 \times 10^{- 4} {weber/m}^{2}$ . If the angle of dip at that place is $60^{\circ}$ , then the vertical component of earth's magnetic field at that place in ${weber/m}^{2}$ will be approximately

Discussion

7876.	The energy flux of sunlight reaching the surface of the earth is 1.388 × 103 W/m2 . How many photons (nearly) per square metre are incident on the Earth per second? Assume that the photons in the sunlight have an average wavelength of 550 nm.
Answer» The energy flux of sunlight reaching the surface of the earth is 1.388 × 103 W/m2 . How many photons (nearly) per square metre are incident on the Earth per second? Assume that the photons in the sunlight have an average wavelength of 550 nm.

Discussion

7877.	Consider the MOS transistor circuit shown in the figure below:Assuming both the MOS transistor are identical with μnCox=2.5μA/V2,VTh=1VandWL=3then the value of current ID is equal to _____μA 8.44
Answer» Consider the MOS transistor circuit shown in the figure below: Assuming both the MOS transistor are identical with $μ_{n} C_{o x} = 2.5 μ A / V^{2}, V_{T h} = 1 V a n d \frac{W}{L} = 3$ then the value of current $I_{D}$ is equal to _____ $μ A$ 8.44

Discussion

7878.	In a TV picture tube electrons are ejected from the cathode with negligible speed and reach a velocity of 5×106m/s in travelling one centimeter. Assuming straight line motion, find the constant force exerted on the electron. The mass of the electron is 9.1×10−31kg.
Answer» In a TV picture tube electrons are ejected from the cathode with negligible speed and reach a velocity of $5 \times 10^{6} m / s$ in travelling one centimeter. Assuming straight line motion, find the constant force exerted on the electron. The mass of the electron is $9.1 \times 10^{- 31} k g .$

Discussion

7879.	The voltage across a lamp is (6.0 \pm 0.1) V and the current flowing through it is (4.0 \pm 0.2) A. Findthe power consumed with maximum permissible error in it.
Answer» The voltage across a lamp is (6.0 \pm 0.1) V and the current flowing through it is (4.0 \pm 0.2) A. Find the power consumed with maximum permissible error in it.

Discussion

7880.	A man of 50 kg mass standing in a gravity free space at a height of 10 m above the floor. He throws a stone of 0.5 kg mass downwards with a speed of 2 m/s. When the stone reaches the floor, the distance of the man above the floor will be
Answer» A man of 50 kg mass standing in a gravity free space at a height of 10 m above the floor. He throws a stone of 0.5 kg mass downwards with a speed of 2 m/s. When the stone reaches the floor, the distance of the man above the floor will be

Discussion

7881.	P-112(QB) Q-22A luminous object is placed at a depth of h through u refractive index. Show that the radius of the circular ground of the cone through which light will pass is r=h/√(u²-1)
Answer» P-112(QB) Q-22 A luminous object is placed at a depth of h through u refractive index. Show that the radius of the circular ground of the cone through which light will pass is r=h/√(u²-1)

Discussion

7882.	Why is potential energy minimum in stable equilibrium
Answer» Why is potential energy minimum in stable equilibrium

Discussion

7883.	what is oligosacchiride?
Answer» what is oligosacchiride?

Discussion

7884.	The electric field due to an infinitely long line of charge at a point is 10 N/C. What is the electric field magnitude at a point which is twice as far from the line of charge?
Answer» The electric field due to an infinitely long line of charge at a point is $10 N/C$ . What is the electric field magnitude at a point which is twice as far from the line of charge?

Discussion

7885.	velocity of bullet is 1/n th times initial velocity . No. of plank required to stop the bulle
Answer» velocity of bullet is 1/n th times initial velocity . No. of plank required to stop the bulle

Discussion

7886.	In a compound microscope, the focal length of the objective lens is 2 cm and that of the eyepiece is 5 cm. When the object is kept at 3 cm in front of the objective lens, the final image is formed at a distance of 50 cm from the eyepiece. Magnifying power of the compound microscope is -
Answer» In a compound microscope, the focal length of the objective lens is $2 cm$ and that of the eyepiece is $5 cm$ . When the object is kept at $3 cm$ in front of the objective lens, the final image is formed at a distance of $50 cm$ from the eyepiece. Magnifying power of the compound microscope is -

Discussion

7887.	To charge q and minus 3 q are placed fixed on x-axis separately by a distance D where should the third charge2q be placed such that it will not experience any force
Answer» To charge q and minus 3 q are placed fixed on x-axis separately by a distance D where should the third charge2q be placed such that it will not experience any force

Discussion

7888.	Would i be correct to think thatNo two bodies can ever physically touch each other. As out body at a particle level are made up of small atoms having electron in outershell.From laws of electrostatics, it would take infinite amount of force to bring two charges infinitely close to each other.Having said that we can never phyisically touch each other.The sensation of touch is basically the electronic repulsion of that we feel at particle level.Would i be correct to think that way?
Answer» Would i be correct to think that No two bodies can ever physically touch each other. As out body at a particle level are made up of small atoms having electron in outershell. From laws of electrostatics, it would take infinite amount of force to bring two charges infinitely close to each other. Having said that we can never phyisically touch each other. The sensation of touch is basically the electronic repulsion of that we feel at particle level. Would i be correct to think that way?

Discussion

7889.	State one application of thermal expansion of liquids.
Answer» State one application of thermal expansion of liquids.

Discussion

7890.	who depends on conc of electrolyte option a electronic conductqmce option b conductivoty
Answer» who depends on conc of electrolyte option a electronic conductqmce option b conductivoty

Discussion

7891.	What should be the velocity of an electronso that its momentum becomes equal to that of a photon of wavelength 5200 ang
Answer» What should be the velocity of an electronso that its momentum becomes equal to that of a photon of wavelength 5200 ang

Discussion

7892.	ntWhen KI is added to AgNO3 solution then why in the electrical double layer of AgI, diffuse layer is of I- ion and not of NO3- ion?n ntn
Answer» ntWhen KI is added to AgNO3 solution then why in the electrical double layer of AgI, diffuse layer is of I- ion and not of NO3- ion?n ntn

Discussion

7893.	Two concentric coils X and Y of radii 16 cm and 10 cm lie in the same vertical plane containing N-S direction. X has 20 turns and carries 16 A. Y has 25 turns and carries 18 A. X has current in anticlockwise direction and Y has current in clockwise direction for an observer, looking at the coils facing the west. The magnitude of net magnetic field at their common centre is
Answer» Two concentric coils X and Y of radii 16 cm and 10 cm lie in the same vertical plane containing N-S direction. X has 20 turns and carries 16 A. Y has 25 turns and carries 18 A. X has current in anticlockwise direction and Y has current in clockwise direction for an observer, looking at the coils facing the west. The magnitude of net magnetic field at their common centre is

Discussion

7894.	A circular coil of radius 4 cm and 20 turns carries a current of 3 ampere. It is placed in a magnetic field of 0.5 T. The magnitude of magnetic dipole moment of the coil will be?
Answer» A circular coil of radius 4 cm and 20 turns carries a current of 3 ampere. It is placed in a magnetic field of 0.5 T. The magnitude of magnetic dipole moment of the coil will be?

Discussion

7895.	10. An electron of 14ev energy incident on hydrogen atom .what would be the kinetic energy of the emitted electron from the system
Answer» 10. An electron of 14ev energy incident on hydrogen atom .what would be the kinetic energy of the emitted electron from the system

Discussion

7896.	When the switches S1 and S2 are closed, the ratio of final energy to the initial energy of the system is
Answer» When the switches $S_{1}$ and $S_{2}$ are closed, the ratio of final energy to the initial energy of the system is

7896.

When the switches S1 and S2 are closed, the ratio of final energy to the initial energy of the system is

Answer»

When the switches $S_{1}$ and $S_{2}$ are closed, the ratio of final energy to the initial energy of the system is

Discussion

7897.	Find the angle of projection of a projectile motion having same values of horizontal component and vertical component of velocity of projection.
Answer» Find the angle of projection of a projectile motion having same values of horizontal component and vertical component of velocity of projection.

Discussion

7898.	Rain is falling at 5m/s making 30 degree with vertical towatrds east. to a man walking at 3m/s on a horizontal road towards east, the rain appears striking at a speed of? a) 2m/s b) 4m/s c)\surd19m/s d)\surd21m/s
Answer» Rain is falling at 5m/s making 30 degree with vertical towatrds east. to a man walking at 3m/s on a horizontal road towards east, the rain appears striking at a speed of? a) 2m/s b) 4m/s c)\surd19m/s d)\surd21m/s

Discussion

7899.	At an instant t ,the coordinates of a particle are x=at2,y=bt2,z=0,then its velocity at that instant when its acceleration is zero will be
Answer» At an instant t ,the coordinates of a particle are x=at2,y=bt2,z=0,then its velocity at that instant when its acceleration is zero will be

Discussion

7900.	The uniform rod of mass 20 kg and length 1.6 m is pivoted at one of its ends and is held in horizontal position, as shown in the diagram. What will be its initial angular acceleration, if it is just released from this position?
Answer» The uniform rod of mass $20 kg$ and length $1.6 m$ is pivoted at one of its ends and is held in horizontal position, as shown in the diagram. What will be its initial angular acceleration, if it is just released from this position?

Discussion

Explore topic-wise InterviewSolutions in .

A small sphere falls from rest in a liquid. Due to viscosity heat is produced. Find the relation between the rate of production of heat and the radius of the sphere at terminal velocity.

8 In which of the following is the radius of the first orbit minimum 1 H-Atom 2 A tritium Atom 3 tiply ionized beryllium 4 double ionized helium

White light is incident normally on a glass plate of thickness 0.50×10−6 m and index of refraction 1.50 . Which wavelengths in the visible region 400 nm−700 nm are strongly reflected by the plate?

If two cars A and B start moving from the same point simultaneously have their positions varying with time t as and. Velocity of A w.r.t B, if their accelerations are equal, will be

The wavelength λ of Kβ X-Ray is given by:

what is the formula for electromagnetic force ? as well as what is the difference between electromagnetic forces and electrostatic forces??

Does angular velocity depend on r? how and why?

Find the change in internal energy of 3 mol of helium gas when its temperature is increased by 2 K.

A simple microscope consists of a concave lens of power −10 D and a convex lens of power +20 D in contact. If the image is formed at infinity, then the magnifying power is x2 , the value of x is : (Take the least distance of distinct vision as D=25 cm)

If V = 1 litre, 10 mole of H2 and 10 mole of N2 gas are mixed at temperature 26 oC then calculate pressure of the gas:

___ consumes 80% less power as compared to ordinary bulbs.

An open rectangular tank 5m × 4m × 3mhigh containing water upto a height of 2m is accelerated horizontally along the larger side. If the acceleration is increased by 20%, the percenatage of water spilt over after increasing the acceleration is

A particle of mass m is moving with a constant velocity v parallel to the x− axis as shown in the figure. Its angular momentum (magnitude) about origin O is

What is unification of forces?

The displacement components at a point in a body for co-ordinate directions x,y &amp; z are u,v and w respectively. Ifu=3x+2y+6zv=x2+3y+2zw=6y+z2The magnitude of shearing strain γxz is

a gaseous compound of the density of 2.5 kg per metre cube at 2 ATM pressure and 546k .find the molecular formula of the compound?

The half-life of a radioactive substance is 20 min. The approximate time interval (t2−t1) between the time t2 when 23 of it had decayed and time t1 when 13 of it had decayed (in min) is ​​​​​​(integer only)

Which of the following graphs correctly represents the variation of 1v versus 1u for a concave mirror?[v = image distance, u = object distance]

17. Draw the intensity pattern for single slit diffraction and double slit interference. Hence, state two differences between interference and diffraction patterns

Four squares plates A, B, C and D having densities σ1, σ2, σ3 and σ4 are kept as shown in figure. If σ1=0.5σ2; σ2=2σ3; σ3=σ44, then location of centre of mass of the system is given by

At a place, the earth's horizontal component of magnetic field is 0.36×10−4 weber/m2. If the angle of dip at that place is 60∘, then the vertical component of earth's magnetic field at that place in weber/m2 will be approximately

The energy flux of sunlight reaching the surface of the earth is 1.388 × 103 W/m2 . How many photons (nearly) per square metre are incident on the Earth per second? Assume that the photons in the sunlight have an average wavelength of 550 nm.

Consider the MOS transistor circuit shown in the figure below:Assuming both the MOS transistor are identical with μnCox=2.5μA/V2,VTh=1VandWL=3then the value of current ID is equal to _____μA 8.44

In a TV picture tube electrons are ejected from the cathode with negligible speed and reach a velocity of 5×106m/s in travelling one centimeter. Assuming straight line motion, find the constant force exerted on the electron. The mass of the electron is 9.1×10−31kg.

The voltage across a lamp is (6.0 \pm 0.1) V and the current flowing through it is (4.0 \pm 0.2) A. Findthe power consumed with maximum permissible error in it.

A man of 50 kg mass standing in a gravity free space at a height of 10 m above the floor. He throws a stone of 0.5 kg mass downwards with a speed of 2 m/s. When the stone reaches the floor, the distance of the man above the floor will be

P-112(QB) Q-22A luminous object is placed at a depth of h through u refractive index. Show that the radius of the circular ground of the cone through which light will pass is r=h/√(u²-1)

Why is potential energy minimum in stable equilibrium

what is oligosacchiride?

The electric field due to an infinitely long line of charge at a point is 10 N/C. What is the electric field magnitude at a point which is twice as far from the line of charge?

velocity of bullet is 1/n th times initial velocity . No. of plank required to stop the bulle

In a compound microscope, the focal length of the objective lens is 2 cm and that of the eyepiece is 5 cm. When the object is kept at 3 cm in front of the objective lens, the final image is formed at a distance of 50 cm from the eyepiece. Magnifying power of the compound microscope is -

To charge q and minus 3 q are placed fixed on x-axis separately by a distance D where should the third charge2q be placed such that it will not experience any force

State one application of thermal expansion of liquids.

who depends on conc of electrolyte option a electronic conductqmce option b conductivoty

What should be the velocity of an electronso that its momentum becomes equal to that of a photon of wavelength 5200 ang

ntWhen KI is added to AgNO3 solution then why in the electrical double layer of AgI, diffuse layer is of I- ion and not of NO3- ion?n ntn

A circular coil of radius 4 cm and 20 turns carries a current of 3 ampere. It is placed in a magnetic field of 0.5 T. The magnitude of magnetic dipole moment of the coil will be?

10. An electron of 14ev energy incident on hydrogen atom .what would be the kinetic energy of the emitted electron from the system

When the switches S1 and S2 are closed, the ratio of final energy to the initial energy of the system is

Find the angle of projection of a projectile motion having same values of horizontal component and vertical component of velocity of projection.

Rain is falling at 5m/s making 30 degree with vertical towatrds east. to a man walking at 3m/s on a horizontal road towards east, the rain appears striking at a speed of? a) 2m/s b) 4m/s c)\surd19m/s d)\surd21m/s

At an instant t ,the coordinates of a particle are x=at2,y=bt2,z=0,then its velocity at that instant when its acceleration is zero will be

The uniform rod of mass 20 kg and length 1.6 m is pivoted at one of its ends and is held in horizontal position, as shown in the diagram. What will be its initial angular acceleration, if it is just released from this position?

The displacement components at a point in a body for co-ordinate directions x,y & z are u,v and w respectively. Ifu=3x+2y+6zv=x2+3y+2zw=6y+z2The magnitude of shearing strain γxz is

The half-life of a radioactive substance is 20 min. The approximate time interval (t2−t1) between the time t2 when 23 of it had decayed and time t1 when 13 of it had decayed (in min) is (integer only)