50278 + Interview Questions in Physics Page 3 InterviewSolution

101.	A particle in a conservative force field has potential energy given by V=20XY/Z the force exerted on it is
Answer» A particle in a conservative force field has potential energy given by V=20XY/Z the force exerted on it is

Discussion

102.	22.) A small point mass m having charge q is at restat a height ho from earth surface by the help ofcharge Q kept on the earth surface. Now q isdisplaced by small displacement on the line joiningthe two charges, the angular frequency ofoscillation of q, i
Answer» 22.) A small point mass m having charge q is at restat a height ho from earth surface by the help ofcharge Q kept on the earth surface. Now q isdisplaced by small displacement on the line joiningthe two charges, the angular frequency ofoscillation of q, i

Discussion

103.	If the magnetic field at ‘P’ can be written as K tan(α2), then K is
Answer» If the magnetic field at ‘P’ can be written as $K$ $tan (\frac{α}{2})$ , then $K$ is

Discussion

104.	y=cos(5-3 t) , dy /dt =
Answer» y=cos(5-3 t) , dy /dt =

Discussion

105.	What is the capacitance of a spherical conductor?
Answer» What is the capacitance of a spherical conductor?

Discussion

106.	A distance between two places at 425 km . If the car drives at the speed of 50 km/hr and start the journey at 10:30 a.m., when does it reach the place?
Answer» A distance between two places at 425 km . If the car drives at the speed of 50 km/hr and start the journey at 10:30 a.m., when does it reach the place?

Discussion

107.	Question 12A student heats a beaker containing ice and water. He measures the temperature of of the content of the beaker as a function of time. Which of the following (Fig. 1.1) would correctly represent the result? Justify your choice.
Answer» Question 12 A student heats a beaker containing ice and water. He measures the temperature of of the content of the beaker as a function of time. Which of the following (Fig. 1.1) would correctly represent the result? Justify your choice.

Discussion

108.	In series LR circuit, XL=3R. Now a capacitor with XC=R is added in series. Ratio of new to old power factor is
Answer» In series $LR$ circuit, $X_{L} = 3 R$ . Now a capacitor with $X_{C} = R$ is added in series. Ratio of new to old power factor is

Discussion

109.	A certain gas obeys P(Vm−b)=RT . The value of (∂Z∂P)T is xbRT. The value of x is ______.
Answer» A certain gas obeys $P (V_{m} - b) = R T$ . The value of ${(\frac{\partial Z}{\partial P})}_{T}$ is $\frac{x b}{R T} .$ The value of $x$ is ______.

Discussion

110.	A cylinder of radius R full of density is rotated about its axis at rad/s. The increase in pressure at the centre of the cylinder will be
Answer» A cylinder of radius R full of density is rotated about its axis at rad/s. The increase in pressure at the centre of the cylinder will be

Discussion

111.	A 100 Ω resistance, a 0.1 μF capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate the value of inductance of inductor at which resonance will ocur. Given that the resonant frequency is 60 Hz
Answer» A $100 Ω$ resistance, a $0.1 μ F$ capacitor and an inductor are connected in series across a $250 V$ supply at variable frequency. Calculate the value of inductance of inductor at which resonance will ocur. Given that the resonant frequency is $60 Hz$

Discussion

112.	On a smooth inclined plane, a body of mass m is attached between two massless springs. The other ends of the springs are fixed to firm supports. If each spring has force constant k, the period of oscillation of the body is
Answer» On a smooth inclined plane, a body of mass m is attached between two massless springs. The other ends of the springs are fixed to firm supports. If each spring has force constant k, the period of oscillation of the body is

Discussion

113.	Two particles of equal mass have coordinates (2 m,4 m,6 m) and (6 m,2 m,8 m). Of these one particle has a velocity →v1=(2^i) m/s and another particle has velocity →v2=(2^j) m/s at time t=0. The coordinate of their centre of mass at time t=1 s will be
Answer» Two particles of equal mass have coordinates $(2 m, 4 m, 6 m)$ and $(6 m, 2 m, 8 m)$ . Of these one particle has a velocity $_{1} = (2^i) m/s$ and another particle has velocity $_{2} = (2^j) m/s$ at time $t = 0$ . The coordinate of their centre of mass at time $t = 1 s$ will be

Discussion

114.	day and night settings for rearview mirrors use
Answer» day and night settings for rearview mirrors use

Discussion

115.	In case of projectile motion, we neglect air resistance. What changes would be there is we take air resistance into consideration?
Answer» In case of projectile motion, we neglect air resistance. What changes would be there is we take air resistance into consideration?

Discussion

116.	A point charge is moving along a straight line with a constant velocity v. Consider a small area A perpendicular to the direction of motion of the charge. Calculate the displacement current through the area when its distance from the charge is x. The value of x is not large so that the electric field at any instant is essentially given by Coulomb's law.
Answer» A point charge is moving along a straight line with a constant velocity $v$ . Consider a small area $A$ perpendicular to the direction of motion of the charge. Calculate the displacement current through the area when its distance from the charge is $x$ . The value of $x$ is not large so that the electric field at any instant is essentially given by Coulomb's law.

Discussion

117.	Prove that height of the tower = αtanβtanαtanβ−tanα
Answer» Prove that height of the tower = $\frac{α t a n β t a n α}{t a n β - t a n α}$

Discussion

118.	A uniform rope of length l lies on a table. If the coefficient of friction is μ, then the maximum length l1 of the hanging part of the rope which can overhang from the edge of the table without sliding down is
Answer» A uniform rope of length $l$ lies on a table. If the coefficient of friction is $μ$ , then the maximum length $l_{1}$ of the hanging part of the rope which can overhang from the edge of the table without sliding down is

Discussion

119.	∫dx5sinx+2cosx+2 is equal to(where C is integration constant)
Answer» $\int \frac{d x}{5 sin x + 2 cos x + 2}$ is equal to (where $C$ is integration constant)

Discussion

120.	The angle of projection of projectile which is projected with certain velocity from ground is π÷8 with horizontal and it's horizontal range is R. The angle with the horizontal for another projectile having same range R and speed is
Answer» The angle of projection of projectile which is projected with certain velocity from ground is π÷8 with horizontal and it's horizontal range is R. The angle with the horizontal for another projectile having same range R and speed is

Discussion

121.	7. If a , b and C are the unit vector s along the incident ray , reflected ray and the outward normal to the reflector . Then what is the relations between a , b and c
Answer» 7. If a , b and C are the unit vector s along the incident ray , reflected ray and the outward normal to the reflector . Then what is the relations between a , b and c

Discussion

122.	Water is flowing at the rate of 500 cm3/sec in a horizontal pipe of uniform cross-section area of 25 cm2. The velocity of flow of water in cm/s is
Answer» Water is flowing at the rate of $500 {cm}^{3} / sec$ in a horizontal pipe of uniform cross-section area of $25 {cm}^{2}$ . The velocity of flow of water in $cm/s$ is

Discussion

123.	A cube of ice floats partly in water and partly in kerosene oil. Find the ratio of the volume of ice immersed in water to the volume in k.oil. Specific gravity of k.oil 0.8 And of ice 0.9
Answer» A cube of ice floats partly in water and partly in kerosene oil. Find the ratio of the volume of ice immersed in water to the volume in k.oil. Specific gravity of k.oil 0.8 And of ice 0.9

123.

A cube of ice floats partly in water and partly in kerosene oil. Find the ratio of the volume of ice immersed in water to the volume in k.oil. Specific gravity of k.oil 0.8 And of ice 0.9

Answer»

A cube of ice floats partly in water and partly in kerosene oil. Find the ratio of the volume of ice immersed in water to the volume in k.oil.

Specific gravity of k.oil 0.8

And of ice 0.9

Discussion

124.	Steam at 100∘C is passed into 1.1 kg of water contained in a calorimeter of water equivalent 0.02 kg at 15∘C till the temperature of the calorimeter and its contents rise at 80∘C. The mass of the stem condensed in kilogram is
Answer» Steam at $100^{\circ} C$ is passed into 1.1 kg of water contained in a calorimeter of water equivalent 0.02 kg at $15^{\circ} C$ till the temperature of the calorimeter and its contents rise at $80^{\circ} C$ . The mass of the stem condensed in kilogram is

Discussion

125.	The flux associated with a spherical surface is 104 Nm2C-1. What will be the flux, if the radius of the spherical shell is doubled?
Answer» The flux associated with a spherical surface is 10⁴ Nm²C^-1. What will be the flux, if the radius of the spherical shell is doubled?

Discussion

126.	A small spherical ball of density p is gently released in a liquid of density s(p>s). Find the initial acceleration of the ball?
Answer» A small spherical ball of density p is gently released in a liquid of density s(p>s). Find the initial acceleration of the ball?

Discussion

127.	An aluminium rod, Young’s modulus 7× 109 N m−2, has a breaking strain of 0.2%. The minimum cross sectional area of the rod in m2 in order to support a load of104 N is
Answer» An aluminium rod, Young’s modulus $7 \times 10^{9} N m^{- 2},$ has a breaking strain of 0.2%. The minimum cross sectional area of the rod in $m^{2}$ in order to support a load of $10^{4}$ N is

Discussion

128.

In Young's double-slit experiment, the point source S is placed slightly off the central axis, as shown in figure. If λ=500 nm, then match the following Column (I)Column (II) (A) Nature and order of interference at point P, OP=10 mm1. Bright fringe of order 80 (B) Nature and order of interference at point O2. Bright fringe of order 262(C) If a transparent paper (refractive index μ=1.45) of thickness t=0.02 mm is pasted on S1, i.e., one of the slits, the nature and order of interference at point P3. Bright fringe of order 62 (D) After inserting the transparent paper in front of Slit S1, the nature and order of interference at O. 4. Bright fringe of order 280

Answer»

In Young's double-slit experiment, the point source $S$ is placed slightly off the central axis, as shown in figure. If $λ = 500 nm$ , then match the following

Column $(I)$	Column $(II)$
$(A)$ Nature and order of interference at point $P$ , $O P = 10 mm$	$1.$ Bright fringe of order $80$
$(B)$ Nature and order of interference at point $O$	$2.$ Bright fringe of order $262$
$(C)$ If a transparent paper (refractive index $μ = 1.45$ ) of thickness $t = 0.02 mm$ is pasted on $S_{1}$ , i.e., one of the slits, the nature and order of interference at point $P$	$3.$ Bright fringe of order $62$
$(D)$ After inserting the transparent paper in front of Slit $S_{1}$ , the nature and order of interference at $O$ .	$4.$ Bright fringe of order $280$

Discussion

129.	Two 29Cu64 nuclei almost touch each other. The electronics repulsive energy of the system will be (R0=1 fm)
Answer» Two $_{29} C u^{64}$ nuclei almost touch each other. The electronics repulsive energy of the system will be $(R_{0} = 1 fm)$

Discussion

130.	A concave mirror and a converging lens (glass with μ=1.5) both have a focal length of 3 cm when in air. When they are in water (μ=43) their new focal lengths are
Answer» A concave mirror and a converging lens (glass with $μ = 1.5$ ) both have a focal length of 3 cm when in air. When they are in water $(μ = \frac{4}{3})$ their new focal lengths are

Discussion

131.	How many significant figures are there in 5000 m ,5.0010^3 m and 5 10^3 m?
Answer» How many significant figures are there in 5000 m ,5.0010^3 m and 5 10^3 m?

Discussion

132.	A parallel plate capacitor of capacity C has been charged so that the potential difference between its plates is V. Now the plates of this capacitor are connected to another uncharged capacitor of capacity 2C. The common potential acquired by system is
Answer» A parallel plate capacitor of capacity C has been charged so that the potential difference between its plates is V. Now the plates of this capacitor are connected to another uncharged capacitor of capacity 2C. The common potential acquired by system is

Discussion

133.	18. If electric and magnetic field is applied cathode rays deflected from their original path?how they deflected from their path if they moves in straight line?
Answer» 18. If electric and magnetic field is applied cathode rays deflected from their original path?how they deflected from their path if they moves in straight line?

Discussion

134.	Velocity vs displacement graph for a body is shown in the figure. Find the acceleration of body when it's displacement is 10 m, considering 1 D motion along a straight line.
Answer» Velocity vs displacement graph for a body is shown in the figure. Find the acceleration of body when it's displacement is $10 m$ , considering $1 D$ motion along a straight line.

Discussion

135.	the coefficient of self induction of two inductor coils arew 20 mH and 40 mH respectively.if the coils are connected in series so as to support each other and the resul†an t induc†an ce is 80 mH then the value of mutual induc†an ce between the coils willbe 1. 5 mH 2.10 mH3.20 mH4.40 mH
Answer» the coefficient of self induction of two inductor coils arew 20 mH and 40 mH respectively.if the coils are connected in series so as to support each other and the resul†an t induc†an ce is 80 mH then the value of mutual induc†an ce between the coils willbe 1. 5 mH 2.10 mH3.20 mH4.40 mH

Discussion

136.	On seeing a board of speed limit, you apply brakes that brings the car from speed of 108 km/h to a speed of 72 km/h, covering a distance of 100 m at a constant deceleration. How much time is required for the given decrease in speed?
Answer» On seeing a board of speed limit, you apply brakes that brings the car from speed of $108 km/h$ to a speed of $72 km/h$ , covering a distance of $100 m$ at a constant deceleration. How much time is required for the given decrease in speed?

Discussion

137.	A beam is supported at its ends by supports which are 12 m apart. Since the load is concentrated at its centre, there is a deflection of 3 cm at the centre, and the deflected beam is in the shape of a parabola. How far from the centre is the deflection 1 cm?
Answer» A beam is supported at its ends by supports which are $12 m$ apart. Since the load is concentrated at its centre, there is a deflection of $3 c m$ at the centre, and the deflected beam is in the shape of a parabola. How far from the centre is the deflection $1 c m ?$

Discussion

138.	In a hydrogen atom, the electron makes the transition from an energy level with quantum number n to another with quantum number (n−1). If n>>1, the frequency of radiation emitted is proportional to
Answer» In a hydrogen atom, the electron makes the transition from an energy level with quantum number $n$ to another with quantum number $(n - 1)$ . If $n >> 1$ , the frequency of radiation emitted is proportional to

Discussion

139.	53.at is the dimensional formula of above formula if E is electric field his planks constan and v is frequency
Answer» 53.at is the dimensional formula of above formula if E is electric field his planks constan and v is frequency

Discussion

140.	71.A ball of radius R carries a positive charge whos volume charge density depends on the distance r from the centre of the ball as = [1-r/R]. Find the electric field at distance r>R
Answer» 71.A ball of radius R carries a positive charge whos volume charge density depends on the distance r from the centre of the ball as = [1-r/R]. Find the electric field at distance r>R

Discussion

141.	39 How scientists found the weight of an atom?
Answer» 39 How scientists found the weight of an atom?

Discussion

142.	What is the displacement of the object when it travels 1/3 of the circle of radius R?
Answer» What is the displacement of the object when it travels 1/3 of the circle of radius R?

Discussion

143.	A current i=2 A flows through the resistance R=10 Ω with what constant speed v (in m/s), the piston (mass =1 kg) must move in upward direction so that temperature of ideal gas present inside cylinder may remain unchanged? Take (g=10 m/s2)
Answer» A current $i = 2 A$ flows through the resistance $R = 10 Ω$ with what constant speed $v$ (in m/s), the piston (mass $= 1 kg$ ) must move in upward direction so that temperature of ideal gas present inside cylinder may remain unchanged? Take ( $g = 10 {m/s}^{2}$ )

Discussion

144.	A photoelectric surface is illuminated successively by monochromatic light of wavelength λ. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is (h = Planck's constant, c = speed of light)
Answer» A photoelectric surface is illuminated successively by monochromatic light of wavelength $λ$ . If the maximum kinetic energy of the emitted photoelectrons in the second case is $3$ times that in the first case, the work function of the surface of the material is ( $h$ = Planck's constant, $c$ = speed of light)

Discussion

145.	The escape speed of a projectile on the earth’s surface is 11.2 km s–1. A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.
Answer» The escape speed of a projectile on the earth’s surface is 11.2 km s–1. A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.

Discussion

146.	is magnetic force stronger then electrostatic force anf gravitational force?
Answer» is magnetic force stronger then electrostatic force anf gravitational force?

Discussion

147.	A body is projected horizontally with a velocity of 10 m/s from the top of an inclined plane of angle 45∘. If the body hit the foot of the plane, the height of the plane (in m) is
Answer» A body is projected horizontally with a velocity of $10 m/s$ from the top of an inclined plane of angle $45^{\circ} .$ If the body hit the foot of the plane, the height of the plane (in $m$ ) is

Discussion

148.	42.Two large conducting plates are placed parallel to each other and they carry equal and opposite charges with surface density $ as shown in the figure . find the electric field in between the plates
Answer» 42.Two large conducting plates are placed parallel to each other and they carry equal and opposite charges with surface density $ as shown in the figure . find the electric field in between the plates

Discussion

149.	What should be the value of angle θ so that light entering normally through the surface AC of a prism with refractive index (n=32), does not cross the 2nd refracting surface AB?
Answer» What should be the value of angle $θ$ so that light entering normally through the surface $A C$ of a prism with refractive index $(n = \frac{3}{2})$ , does not cross the $2^{nd}$ refracting surface $A B$ ?

Discussion

150.	2 rods of equal length l and mass M are kept along X and Y axis respectively such that their centre of mass lies at origin. The moment of inertia about the line y=x is?
Answer» 2 rods of equal length l and mass M are kept along X and Y axis respectively such that their centre of mass lies at origin. The moment of inertia about the line y=x is?

Discussion

Explore topic-wise InterviewSolutions in .

A particle in a conservative force field has potential energy given by V=20XY/Z the force exerted on it is

22.) A small point mass m having charge q is at restat a height ho from earth surface by the help ofcharge Q kept on the earth surface. Now q isdisplaced by small displacement on the line joiningthe two charges, the angular frequency ofoscillation of q, i

If the magnetic field at ‘P’ can be written as K tan(α2), then K is

y=cos(5-3 t) , dy /dt =

What is the capacitance of a spherical conductor?

A distance between two places at 425 km . If the car drives at the speed of 50 km/hr and start the journey at 10:30 a.m., when does it reach the place?

Question 12A student heats a beaker containing ice and water. He measures the temperature of of the content of the beaker as a function of time. Which of the following (Fig. 1.1) would correctly represent the result? Justify your choice.

In series LR circuit, XL=3R. Now a capacitor with XC=R is added in series. Ratio of new to old power factor is

A certain gas obeys P(Vm−b)=RT . The value of (∂Z∂P)T is xbRT. The value of x is ______.

A cylinder of radius R full of density is rotated about its axis at rad/s. The increase in pressure at the centre of the cylinder will be

A 100 Ω resistance, a 0.1 μF capacitor and an inductor are connected in series across a 250 V supply at variable frequency. Calculate the value of inductance of inductor at which resonance will ocur. Given that the resonant frequency is 60 Hz

On a smooth inclined plane, a body of mass m is attached between two massless springs. The other ends of the springs are fixed to firm supports. If each spring has force constant k, the period of oscillation of the body is

Two particles of equal mass have coordinates (2 m,4 m,6 m) and (6 m,2 m,8 m). Of these one particle has a velocity →v1=(2^i) m/s and another particle has velocity →v2=(2^j) m/s at time t=0. The coordinate of their centre of mass at time t=1 s will be

day and night settings for rearview mirrors use

In case of projectile motion, we neglect air resistance. What changes would be there is we take air resistance into consideration?

Prove that height of the tower = αtanβtanαtanβ−tanα

A uniform rope of length l lies on a table. If the coefficient of friction is μ, then the maximum length l1 of the hanging part of the rope which can overhang from the edge of the table without sliding down is

∫dx5sinx+2cosx+2 is equal to(where C is integration constant)

The angle of projection of projectile which is projected with certain velocity from ground is π÷8 with horizontal and it's horizontal range is R. The angle with the horizontal for another projectile having same range R and speed is

7. If a , b and C are the unit vector s along the incident ray , reflected ray and the outward normal to the reflector . Then what is the relations between a , b and c

Water is flowing at the rate of 500 cm3/sec in a horizontal pipe of uniform cross-section area of 25 cm2. The velocity of flow of water in cm/s is

A cube of ice floats partly in water and partly in kerosene oil. Find the ratio of the volume of ice immersed in water to the volume in k.oil. Specific gravity of k.oil 0.8 And of ice 0.9

Steam at 100∘C is passed into 1.1 kg of water contained in a calorimeter of water equivalent 0.02 kg at 15∘C till the temperature of the calorimeter and its contents rise at 80∘C. The mass of the stem condensed in kilogram is

The flux associated with a spherical surface is 104 Nm2C-1. What will be the flux, if the radius of the spherical shell is doubled?

A small spherical ball of density p is gently released in a liquid of density s(p&gt;s). Find the initial acceleration of the ball?

An aluminium rod, Young’s modulus 7× 109 N m−2, has a breaking strain of 0.2%. The minimum cross sectional area of the rod in m2 in order to support a load of104 N is

Two 29Cu64 nuclei almost touch each other. The electronics repulsive energy of the system will be (R0=1 fm)

A concave mirror and a converging lens (glass with μ=1.5) both have a focal length of 3 cm when in air. When they are in water (μ=43) their new focal lengths are

How many significant figures are there in 5000 m ,5.00*10^3 m and 5 * 10^3 m?

A parallel plate capacitor of capacity C has been charged so that the potential difference between its plates is V. Now the plates of this capacitor are connected to another uncharged capacitor of capacity 2C. The common potential acquired by system is

18. If electric and magnetic field is applied cathode rays deflected from their original path?how they deflected from their path if they moves in straight line?

Velocity vs displacement graph for a body is shown in the figure. Find the acceleration of body when it's displacement is 10 m, considering 1 D motion along a straight line.

the coefficient of self induction of two inductor coils arew 20 mH and 40 mH respectively.if the coils are connected in series so as to support each other and the resul†an t induc†an ce is 80 mH then the value of mutual induc†an ce between the coils willbe 1. 5 mH 2.10 mH3.20 mH4.40 mH

On seeing a board of speed limit, you apply brakes that brings the car from speed of 108 km/h to a speed of 72 km/h, covering a distance of 100 m at a constant deceleration. How much time is required for the given decrease in speed?

A beam is supported at its ends by supports which are 12 m apart. Since the load is concentrated at its centre, there is a deflection of 3 cm at the centre, and the deflected beam is in the shape of a parabola. How far from the centre is the deflection 1 cm?

In a hydrogen atom, the electron makes the transition from an energy level with quantum number n to another with quantum number (n−1). If n&gt;&gt;1, the frequency of radiation emitted is proportional to

53.at is the dimensional formula of above formula if E is electric field his planks constan and v is frequency

71.A ball of radius R carries a positive charge whos volume charge density depends on the distance r from the centre of the ball as = [1-r/R]. Find the electric field at distance r>R

39 How scientists found the weight of an atom?

What is the displacement of the object when it travels 1/3 of the circle of radius R?

A current i=2 A flows through the resistance R=10 Ω with what constant speed v (in m/s), the piston (mass =1 kg) must move in upward direction so that temperature of ideal gas present inside cylinder may remain unchanged? Take (g=10 m/s2)

The escape speed of a projectile on the earth’s surface is 11.2 km s–1. A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.

is magnetic force stronger then electrostatic force anf gravitational force?

A body is projected horizontally with a velocity of 10 m/s from the top of an inclined plane of angle 45∘. If the body hit the foot of the plane, the height of the plane (in m) is

42.Two large conducting plates are placed parallel to each other and they carry equal and opposite charges with surface density $ as shown in the figure . find the electric field in between the plates

What should be the value of angle θ so that light entering normally through the surface AC of a prism with refractive index (n=32), does not cross the 2nd refracting surface AB?

2 rods of equal length l and mass M are kept along X and Y axis respectively such that their centre of mass lies at origin. The moment of inertia about the line y=x is?

A small spherical ball of density p is gently released in a liquid of density s(p>s). Find the initial acceleration of the ball?

How many significant figures are there in 5000 m ,5.0010^3 m and 5 10^3 m?

In a hydrogen atom, the electron makes the transition from an energy level with quantum number n to another with quantum number (n−1). If n>>1, the frequency of radiation emitted is proportional to