50278 + Interview Questions in Physics Page 185 InterviewSolution

9201.	The velocity of an electron if its debroglie wavelength equal to the dis†an ce it travels in one secon
Answer» The velocity of an electron if its debroglie wavelength equal to the dis†an ce it travels in one secon

Discussion

9202.	A unit vector has magnitude equal to
Answer» A unit vector has magnitude equal to

Discussion

9203.	semi vertex of the conical surface ( obtained by taking dipole moment as axis ) on which electric field by dipole becomes normal to moment of the dipole is equal to tan inverse root 2 How ?
Answer» semi vertex of the conical surface ( obtained by taking dipole moment as axis ) on which electric field by dipole becomes normal to moment of the dipole is equal to tan inverse root 2 How ?

Discussion

9204.	When the distance between the charged particles is halved, the force between them becomes
Answer» When the distance between the charged particles is halved, the force between them becomes

9204.

When the distance between the charged particles is halved, the force between them becomes

Answer»

When the distance between the charged particles is halved, the force between them becomes

Discussion

9205.	Ahollow charged conductor has a tiny hole cut into its surface. Showthat the electric field in the hole is ,where is the unit vector in the outwardnormal direction, and isthe surface charge density near the hole.
Answer» A hollow charged conductor has a tiny hole cut into its surface. Show that the electric field in the hole is , where is the unit vector in the outward normal direction, and is the surface charge density near the hole.

Discussion

9206.	The cylindrical tube of a spray pump has a cross-section of 8.0 cm2 one end of which has 40 fine holes each of diameter 1.0 mm. If the liquid flow inside the tube is 1.5 m min¯¹, what is the speed of ejection of the liquid through the holes ?
Answer» The cylindrical tube of a spray pump has a cross-section of 8.0 cm2 one end of which has 40 fine holes each of diameter 1.0 mm. If the liquid flow inside the tube is 1.5 m min¯¹, what is the speed of ejection of the liquid through the holes ?

Discussion

9207.	what is the value of1light year in meter
Answer» what is the value of1light year in meter

Discussion

9208.	The packing fraction of the element that crystallises in simple cubic arrangement is:
Answer» The packing fraction of the element that crystallises in simple cubic arrangement is:

Discussion

9209.	If I place a random arrangement of dielectrics like this in my capacitor, how do I find my new capacitance?
Answer» If I place a random arrangement of dielectrics like this in my capacitor, how do I find my new capacitance?

Discussion

9210.	What are the equivalents when they are connected in parallel if :-- 1. The resistivity of a subs†an ce is ρ1 and other is ρ2 ; 2 .The conductivity of a subs†an ce is σ1 and other is σ2
Answer» What are the equivalents when they are connected in parallel if :-- 1. The resistivity of a subs†an ce is ρ1 and other is ρ2 ; 2 .The conductivity of a subs†an ce is σ1 and other is σ2

Discussion

9211.	ABCDE is a pentagon. Forces −−→AB,−−→AE,−−→DC,−−→ED act at a point. Which force should be added to this system to make the resultant 2−−→AC
Answer» $A B C D E$ is a pentagon. Forces $- - \to A B, - - \to A E, - - \to D C, - - \to E D$ act at a point. Which force should be added to this system to make the resultant $2 - - \to A C$

Discussion

9212.	How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 1.5 × 10⁸ km.
Answer» How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 1.5 × 10⁸ km.

Discussion

9213.	17 Why is the width of depletion region large when p-n junction diode is lightly doped and vice versa?
Answer» 17 Why is the width of depletion region large when p-n junction diode is lightly doped and vice versa?

Discussion

9214.	When radiation is incident on a photoelectron emitter, the stopping potential is found to be 9 volts. If e/m for the electron is 1.8×1011 Ckg−1 the maximum velocity of the ejected electrons is
Answer» When radiation is incident on a photoelectron emitter, the stopping potential is found to be 9 volts. If e/m for the electron is $1.8 \times 10^{11} C k g^{- 1}$ the maximum velocity of the ejected electrons is

Discussion

9215.	Define the term 'mutual inductance' between two coils. Obtain the expression for mutual inductance of a pair of long coaxial solenoids each of length l and radii r1 and r2(r2>>r1). Total number of turns in the two solenoids are N1 and N2 respectively.
Answer» Define the term 'mutual inductance' between two coils. Obtain the expression for mutual inductance of a pair of long coaxial solenoids each of length l and radii $r_{1}$ and $r_{2} (r_{2} >> r_{1})$ . Total number of turns in the two solenoids are $N_{1}$ and $N_{2}$ respectively.

Discussion

9216.	The escape velocity from the surface of the earth of radius R and density ρ is given by
Answer» The escape velocity from the surface of the earth of radius R and density $ρ$ is given by

Discussion

9217.	A proton is fired from very far away source towards a nucleus with charge q = 120e, where 'e' is the electronic charge. It makes a closest approach of 10 fm to the nucleus. The de Broglie wavelength (in units of fm) of the proton at its start is___? (Take the proton mass, mp = (5/3) × 10−27kg; h/e = 4.2 × 10−15 J.s/C;14π ε0 = 9 × 109 m/F; 1fm = 10−15 m)
Answer» A proton is fired from very far away source towards a nucleus with charge q = 120e, where 'e' is the electronic charge. It makes a closest approach of 10 fm to the nucleus. The de Broglie wavelength (in units of fm) of the proton at its start is___? (Take the proton mass, mp = (5/3) $\times 10^{- 27} k g; h / e = 4.2 \times 10^{- 15} J . s / C; \frac{1}{4 π ε_{0}} = 9 \times 10^{9} m / F; 1 f m = 10^{- 15} m)$

Discussion

9218.	Pressureof 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 gof another ideal gas B is introduced in the same flask at sametemperature the pressure becomes 3 bar. Find a relationship betweentheir molecular masses.
Answer» Pressure of 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 g of another ideal gas B is introduced in the same flask at same temperature the pressure becomes 3 bar. Find a relationship between their molecular masses.

Discussion

9219.	If there is no deflection in the galvanometer connected in a circuit shown in figure, then the ratio of lengths AC / CB is
Answer» If there is no deflection in the galvanometer connected in a circuit shown in figure, then the ratio of lengths $A C / C B$ is

Discussion

9220.	The number of turns in primary and secondary windings of a transformer are 1000 and 100 respectively. If 200V dc voltage is impressed across the primary terminals, the voltage across secondary terminals is
Answer» The number of turns in primary and secondary windings of a transformer are 1000 and 100 respectively. If 200V dc voltage is impressed across the primary terminals, the voltage across secondary terminals is

Discussion

9221.	If the energy in the first excited state in hydrogen atom is 23.8 eV then the potential energy of a hydrogen atom in the ground state can be assumed to be (1) 10eV (2) 23.3eV (3) -13.6eV (4) Zero
Answer» If the energy in the first excited state in hydrogen atom is 23.8 eV then the potential energy of a hydrogen atom in the ground state can be assumed to be (1) 10eV (2) 23.3eV (3) -13.6eV (4) Zero

Discussion

9222.	The upper portion of an inclined plane of inclination α is smooth and the lower portion is rough. A particle slides down from rest from the top and just comes to rest at the foot. If the ratio of smooth length to rough length is m : n, find the coefficient of friction
Answer» The upper portion of an inclined plane of inclination α is smooth and the lower portion is rough. A particle slides down from rest from the top and just comes to rest at the foot. If the ratio of smooth length to rough length is m : n, find the coefficient of friction

Discussion

9223.	five masses are placed on the vertices of a recular pentagon a sixth mass is placed at the center of pentagon then resul†an t force on mo
Answer» five masses are placed on the vertices of a recular pentagon a sixth mass is placed at the center of pentagon then resul†an t force on mo

Discussion

9224.	A block of mass m attached to an ideal spring of spring constant K is placed on a smooth horizontal surface between two fixed elastic walls AB and CD as shown. The block is at a distance d from CD and spring is in its natural position. The maximum velocity with which the block can be projected towards CD so that block performs complete SHM.
Answer» A block of mass m attached to an ideal spring of spring constant K is placed on a smooth horizontal surface between two fixed elastic walls AB and CD as shown. The block is at a distance d from CD and spring is in its natural position. The maximum velocity with which the block can be projected towards CD so that block performs complete SHM.

9224.

A block of mass m attached to an ideal spring of spring constant K is placed on a smooth horizontal surface between two fixed elastic walls AB and CD as shown. The block is at a distance d from CD and spring is in its natural position. The maximum velocity with which the block can be projected towards CD so that block performs complete SHM.

Answer»

A block of mass m attached to an ideal spring of spring constant K is placed on a smooth horizontal surface between two fixed elastic walls AB and CD as shown. The block is at a distance d from CD and spring is in its natural position. The maximum velocity with which the block can be projected towards CD so that block performs complete SHM.

Discussion

9225.	Pick the odd one out a)work,energy,heat b)young's modulus,pressure,stress c)emf,voltage,potential difference d)voltage,current,resistance
Answer» Pick the odd one out a)work,energy,heat b)young's modulus,pressure,stress c)emf,voltage,potential difference d)voltage,current,resistance

9225.

Pick the odd one out a)work,energy,heat b)young's modulus,pressure,stress c)emf,voltage,potential difference d)voltage,current,resistance

Answer»

Pick the odd one out

a)work,energy,heat

b)young's modulus,pressure,stress

c)emf,voltage,potential difference

d)voltage,current,resistance

Discussion

9226.	How to find maximum magnetic moment?
Answer» How to find maximum magnetic moment?

Discussion

9227.	Find the mass M of the hanging block in figure whic will prevent the smaller block from slipping over the triangular block. All the surfaces are frictionless and the string and the pulleys are light.
Answer» Find the mass M of the hanging block in figure whic will prevent the smaller block from slipping over the triangular block. All the surfaces are frictionless and the string and the pulleys are light.

9227.

Find the mass M of the hanging block in figure whic will prevent the smaller block from slipping over the triangular block. All the surfaces are frictionless and the string and the pulleys are light.

Answer»

Find the mass M of the hanging block in figure whic will prevent the smaller block from slipping over the triangular block. All the surfaces are frictionless and the string and the pulleys are light.

Discussion

9228.	In Young's double slit experiment, having slits of equal width, β is the fringe width and I0 is the maximum intensity. At a distance x from the central bright fringe, the intensity will be,
Answer» In Young's double slit experiment, having slits of equal width, $β$ is the fringe width and $I_{0}$ is the maximum intensity. At a distance $x$ from the central bright fringe, the intensity will be,

Discussion

9229.	With the increase in intensity of light, the NAR
Answer» With the increase in intensity of light, the NAR

Discussion

9230.	Why are the air molecules in our atmosphere not escaping into outer space?
Answer» Why are the air molecules in our atmosphere not escaping into outer space?

Discussion

9231.	The potential energy of a particle of mass m at a distance r from a fixed point O is given by V(r)=kr22, where k is a positive constant of appropriate dimensions. This particle is moving in a circular orbit of radius R about the point O. If v is the speed of the particle and L is the magnitude of its angular momentum about O, which of the following statements is (are) true ?
Answer» The potential energy of a particle of mass m at a distance r from a fixed point O is given by $V (r) = \frac{k r^{2}}{2}$ , where k is a positive constant of appropriate dimensions. This particle is moving in a circular orbit of radius R about the point O. If $v$ is the speed of the particle and $L$ is the magnitude of its angular momentum about O, which of the following statements is (are) true ?

Discussion

9232.	The potential function of an electric field is given by V=2x2. Determine strength of the electrostatic field at the point (2 m,0,3 m).
Answer» The potential function of an electric field is given by $V = 2 x^{2} .$ Determine strength of the electrostatic field at the point $(2 m, 0, 3 m) .$

Discussion

9233.	A body which was intially at rest covers a distance of 30 m in first 3 seconds. What is the acceleration? [3 MARKS]
Answer» A body which was intially at rest covers a distance of $30 m$ in first 3 seconds. What is the acceleration? [3 MARKS]

Discussion

9234.	A carbon resistance is having a followingcoding green, orange, black and gold. Its resistance is
Answer» A carbon resistance is having a followingcoding green, orange, black and gold. Its resistance is

Discussion

9235.	The masses of 10 kg and 20 kg respectively are connected by a massless spring in fig. A force of 200 newton acts on the 20 kg mass. At the instant shown, the 10 kg mass has acceleration 12 m/sec2. What is the acceleration of 20 kg mass?
Answer» The masses of $10 kg$ and $20 kg$ respectively are connected by a massless spring in fig. A force of $200$ newton acts on the $20 kg$ mass. At the instant shown, the $10 kg$ mass has acceleration $12 {m/sec}^{2}$ . What is the acceleration of $20 kg$ mass?

Discussion

9236.	Suppose a diatomic gas gets ionised to a certain extent without any expenditure of heat energy. If the fractional change in the number of moles of the gas be η, then ignoring any energy loss, the fractional change in the temperature of the gas can be
Answer» Suppose a diatomic gas gets ionised to a certain extent without any expenditure of heat energy. If the fractional change in the number of moles of the gas be $η$ , then ignoring any energy loss, the fractional change in the temperature of the gas can be

Discussion

9237.	A marble of mass x and diameter 2r is gently released in a tall cylinder containing honey. If the marble displaces mass y (<x) of the liquid, then the terminal velocity is proportional to
Answer» A marble of mass $x$ and diameter $2 r$ is gently released in a tall cylinder containing honey. If the marble displaces mass $y (< x)$ of the liquid, then the terminal velocity is proportional to

Discussion

9238.	A particle is moving on a circular path of Radius R such that its speed is increasing at rate of \pm. The angle between velocity and total accelration at moment when speed of the partcle is v., is given by 1. = 1/sin (v/\pmR) 2. = 1/sin (v/ R\pm) 3. = 1/cos (v/\pmR) 4. = 1/tan (v/ R\pm)
Answer» A particle is moving on a circular path of Radius R such that its speed is increasing at rate of \pm. The angle between velocity and total accelration at moment when speed of the partcle is v., is given by 1. = 1/sin (v/\pmR) 2. = 1/sin (v/ R\pm) 3. = 1/cos (v/\pmR) 4. = 1/tan (v/ R\pm)

Discussion

9239.	If the energy stored in spring A is 5 J, then the energy stored in spring B, under the same stretching force F will be:
Answer» If the energy stored in spring $A is 5 J$ , then the energy stored in spring $B$ , under the same stretching force $F$ will be:

Discussion

9240.	If v=at+bt3 where, v=velocity and t is the time. The dimensional formula of a and b respectively are
Answer» If $v = \frac{a}{t} + b t^{3}$ where, $v = velocity$ and $t$ is the time. The dimensional formula of $a$ and $b$ respectively are

Discussion

9241.	Q:- If a copper wire is stretched to make it 0.1% longer, then the percentage change in its resis†an ce is approximately 1. 0.1% 2. 0.2
Answer» Q:- If a copper wire is stretched to make it 0.1% longer, then the percentage change in its resis†an ce is approximately 1. 0.1% 2. 0.2

Discussion

9242.	Water flows in a rectangular concrete channel and undergoes a hydraulic jump such that half of its mechanical energy gets dissipated. If the channel carries 10cumecs water energy at a depth of 0.6 m and the width of channel is 5 m, the Froude number after the jump is . 0.2
Answer» Water flows in a rectangular concrete channel and undergoes a hydraulic jump such that half of its mechanical energy gets dissipated. If the channel carries 10cumecs water energy at a depth of 0.6 m and the width of channel is 5 m, the Froude number after the jump is . 0.2

Discussion

9243.	Rain is falling vertically downward in a region with speed 4 metre per second.A boy walking on ground with speed 3m/s observes the rain .The speed of rain wet the boy is.
Answer» Rain is falling vertically downward in a region with speed 4 metre per second.A boy walking on ground with speed 3m/s observes the rain .The speed of rain wet the boy is.

Discussion

9244.	For the circuit shown, which of the following is incorrect?
Answer» For the circuit shown, which of the following is incorrect?

Discussion

9245.	The least count of the voltmeter shown below is:(1) 0.1 V(2) 0.01 V(3) 0.02 V(4) 0.2 V
Answer» The least count of the voltmeter shown below is: (1) 0.1 V (2) 0.01 V (3) 0.02 V (4) 0.2 V

Discussion

9246.	Two bar magnets of same length and breadth having magnetic moments M and 4M respectively are joined with likes poles together and suspended in a uniform magnetic field B, it oscillates with time period T=√3 s. If the polarity of one of the magnet is reversed and the combination is again made to oscillate in the same field. Find the new time period of this combination.
Answer» Two bar magnets of same length and breadth having magnetic moments $M$ and $4 M$ respectively are joined with likes poles together and suspended in a uniform magnetic field $B$ , it oscillates with time period $T = \sqrt{3} s$ . If the polarity of one of the magnet is reversed and the combination is again made to oscillate in the same field. Find the new time period of this combination.

Discussion

9247.	Consider a 72 cm long wire AB as shown in the figure. The galvanometer jockey is placed at P on AB at a distance of x cm from A. The galvanometer shows zero deflection. The value of x, to the nearest integer, is _____.
Answer» Consider a $72 cm$ long wire $A B$ as shown in the figure. The galvanometer jockey is placed at $P$ on $A B$ at a distance of $x cm$ from $A$ . The galvanometer shows zero deflection. The value of $x$ , to the nearest integer, is _____.

Discussion

9248.	A ray of light falls on the surface of a spherical glass paper weight making an angle α with the normal and is refracted in the medium at an angle β. The angle of deviation of the emergent ray from the direction of the incident ray is
Answer» A ray of light falls on the surface of a spherical glass paper weight making an angle $α$ with the normal and is refracted in the medium at an angle $β$ . The angle of deviation of the emergent ray from the direction of the incident ray is

Discussion

9249.	A real image is formed by a mirror when:
Answer» A real image is formed by a mirror when:

Discussion

9250.	25. if i,j,k are unit orthogonal vector and a is a vector, if
Answer» 25. if i,j,k are unit orthogonal vector and a is a vector, if

Discussion

Explore topic-wise InterviewSolutions in .

The velocity of an electron if its debroglie wavelength equal to the dis†an ce it travels in one secon

A unit vector has magnitude equal to

semi vertex of the conical surface ( obtained by taking dipole moment as axis ) on which electric field by dipole becomes normal to moment of the dipole is equal to tan inverse root 2 How ?

When the distance between the charged particles is halved, the force between them becomes

Ahollow charged conductor has a tiny hole cut into its surface. Showthat the electric field in the hole is ,where is the unit vector in the outwardnormal direction, and isthe surface charge density near the hole.

The cylindrical tube of a spray pump has a cross-section of 8.0 cm2 one end of which has 40 fine holes each of diameter 1.0 mm. If the liquid flow inside the tube is 1.5 m min¯¹, what is the speed of ejection of the liquid through the holes ?

what is the value of1light year in meter

The packing fraction of the element that crystallises in simple cubic arrangement is:

If I place a random arrangement of dielectrics like this in my capacitor, how do I find my new capacitance?

What are the equivalents when they are connected in parallel if :-- 1. The resistivity of a subs†an ce is ρ1 and other is ρ2 ; 2 .The conductivity of a subs†an ce is σ1 and other is σ2

ABCDE is a pentagon. Forces −−→AB,−−→AE,−−→DC,−−→ED act at a point. Which force should be added to this system to make the resultant 2−−→AC

How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 1.5 × 10⁸ km.

17 Why is the width of depletion region large when p-n junction diode is lightly doped and vice versa?

When radiation is incident on a photoelectron emitter, the stopping potential is found to be 9 volts. If e/m for the electron is 1.8×1011 Ckg−1 the maximum velocity of the ejected electrons is

Define the term 'mutual inductance' between two coils. Obtain the expression for mutual inductance of a pair of long coaxial solenoids each of length l and radii r1 and r2(r2&gt;&gt;r1). Total number of turns in the two solenoids are N1 and N2 respectively.

The escape velocity from the surface of the earth of radius R and density ρ is given by

Pressureof 1 g of an ideal gas A at 27 °C is found to be 2 bar. When 2 gof another ideal gas B is introduced in the same flask at sametemperature the pressure becomes 3 bar. Find a relationship betweentheir molecular masses.

If there is no deflection in the galvanometer connected in a circuit shown in figure, then the ratio of lengths AC / CB is

The number of turns in primary and secondary windings of a transformer are 1000 and 100 respectively. If 200V dc voltage is impressed across the primary terminals, the voltage across secondary terminals is

If the energy in the first excited state in hydrogen atom is 23.8 eV then the potential energy of a hydrogen atom in the ground state can be assumed to be (1) 10eV (2) 23.3eV (3) -13.6eV (4) Zero

The upper portion of an inclined plane of inclination α is smooth and the lower portion is rough. A particle slides down from rest from the top and just comes to rest at the foot. If the ratio of smooth length to rough length is m : n, find the coefficient of friction

five masses are placed on the vertices of a recular pentagon a sixth mass is placed at the center of pentagon then resul†an t force on mo

Pick the odd one out a)work,energy,heat b)young's modulus,pressure,stress c)emf,voltage,potential difference d)voltage,current,resistance

How to find maximum magnetic moment?

Find the mass M of the hanging block in figure whic will prevent the smaller block from slipping over the triangular block. All the surfaces are frictionless and the string and the pulleys are light.

In Young's double slit experiment, having slits of equal width, β is the fringe width and I0 is the maximum intensity. At a distance x from the central bright fringe, the intensity will be,

With the increase in intensity of light, the NAR

Why are the air molecules in our atmosphere not escaping into outer space?

The potential function of an electric field is given by V=2x2. Determine strength of the electrostatic field at the point (2 m,0,3 m).

A body which was intially at rest covers a distance of 30 m in first 3 seconds. What is the acceleration? [3 MARKS]

A carbon resistance is having a followingcoding green, orange, black and gold. Its resistance is

The masses of 10 kg and 20 kg respectively are connected by a massless spring in fig. A force of 200 newton acts on the 20 kg mass. At the instant shown, the 10 kg mass has acceleration 12 m/sec2. What is the acceleration of 20 kg mass?

Suppose a diatomic gas gets ionised to a certain extent without any expenditure of heat energy. If the fractional change in the number of moles of the gas be η, then ignoring any energy loss, the fractional change in the temperature of the gas can be

A marble of mass x and diameter 2r is gently released in a tall cylinder containing honey. If the marble displaces mass y (&lt;x) of the liquid, then the terminal velocity is proportional to

A particle is moving on a circular path of Radius R such that its speed is increasing at rate of \pm. The angle between velocity and total accelration at moment when speed of the partcle is v., is given by 1. = 1/sin (v/\pmR) 2. = 1/sin (v/ R\pm) 3. = 1/cos (v/\pmR) 4. = 1/tan (v/ R\pm)

If the energy stored in spring A is 5 J, then the energy stored in spring B, under the same stretching force F will be:

If v=at+bt3 where, v=velocity and t is the time. The dimensional formula of a and b respectively are

Q:- If a copper wire is stretched to make it 0.1% longer, then the percentage change in its resis†an ce is approximately 1. 0.1% 2. 0.2

Water flows in a rectangular concrete channel and undergoes a hydraulic jump such that half of its mechanical energy gets dissipated. If the channel carries 10cumecs water energy at a depth of 0.6 m and the width of channel is 5 m, the Froude number after the jump is . 0.2

Rain is falling vertically downward in a region with speed 4 metre per second.A boy walking on ground with speed 3m/s observes the rain .The speed of rain wet the boy is.

For the circuit shown, which of the following is incorrect?

The least count of the voltmeter shown below is:(1) 0.1 V(2) 0.01 V(3) 0.02 V(4) 0.2 V

Consider a 72 cm long wire AB as shown in the figure. The galvanometer jockey is placed at P on AB at a distance of x cm from A. The galvanometer shows zero deflection. The value of x, to the nearest integer, is _____.

A ray of light falls on the surface of a spherical glass paper weight making an angle α with the normal and is refracted in the medium at an angle β. The angle of deviation of the emergent ray from the direction of the incident ray is

A real image is formed by a mirror when:

25. if i,j,k are unit orthogonal vector and a is a vector, if

Define the term 'mutual inductance' between two coils. Obtain the expression for mutual inductance of a pair of long coaxial solenoids each of length l and radii r1 and r2(r2>>r1). Total number of turns in the two solenoids are N1 and N2 respectively.

A marble of mass x and diameter 2r is gently released in a tall cylinder containing honey. If the marble displaces mass y (<x) of the liquid, then the terminal velocity is proportional to