50278 + Interview Questions in Physics Page 74 InterviewSolution

3651.	A river is flowing with a speed of 1 kmh−1. A swimmer wants to go to point C starting form A. He swims with a speed of 5 kmh−1 at an angle θ with the river flow. If AB=BC=400 m, at what angle with the river bank should the swimmer swim?
Answer» A river is flowing with a speed of $1 {kmh}^{- 1}$ . A swimmer wants to go to point $C$ starting form $A$ . He swims with a speed of $5 {kmh}^{- 1}$ at an angle $θ$ with the river flow. If $AB = BC = 400 m$ , at what angle with the river bank should the swimmer swim?

Discussion

3652.	A force acting on body of 1 tonne at rest. The body acquired a velocity of 1ms`1 in a distance of 10m.find the force
Answer» A force acting on body of 1 tonne at rest. The body acquired a velocity of 1ms`1 in a distance of 10m.find the force

Discussion

3653.	A square of side 2 m is placed in a uniform magnetic field B=2 T in a direction perpendicular to the plane of square and pointing inwards Equal current i=3 A is flowing in the direction shown in figure. The magnitude of magnetic force acting on the loop will be :
Answer» A square of side $2 m$ is placed in a uniform magnetic field $B = 2 T$ in a direction perpendicular to the plane of square and pointing inwards Equal current $i = 3 A$ is flowing in the direction shown in figure. The magnitude of magnetic force acting on the loop will be :

Discussion

3654.	A semiconductor is known to have an electron concentration of 8×1013/cc and hole concentration of 5×1012/cc . The semiconductor is
Answer» A semiconductor is known to have an electron concentration of $8 \times 10^{13} / c c$ and hole concentration of $5 \times 10^{12} / c c$ . The semiconductor is

Discussion

3655.	Find the number of moles of oxygen atoms present in 1.2×1026 atoms of oxygen. (Given: NA=6×1023)
Answer» Find the number of moles of oxygen atoms present in $1.2 \times 10^{26}$ atoms of oxygen. (Given: $N_{A} = 6 \times 10^{23}$ )

Discussion

3656.	The rear side of a truck is open and a box of mass 20 kg is placed on the truck 4 m away from the open end. The coefficient of friction between the box and the surface is 0.15. The truck starts from rest with an acceleration of 2 m s−2 on a straight road. The box will fall off the truck when it is at a distance from the starting point equal to (take g=10 ms−2)
Answer» The rear side of a truck is open and a box of mass $20 kg$ is placed on the truck $4 m$ away from the open end. The coefficient of friction between the box and the surface is $0.15$ . The truck starts from rest with an acceleration of $2 {m s}^{- 2}$ on a straight road. The box will fall off the truck when it is at a distance from the starting point equal to (take $g = 10 m s^{- 2}$ )

Discussion

3657.	A refrigerator freezes water at 0∘C into 10 kg ice at 0∘C in a time interval of 30 min. Assuming the room temperature to be 22∘C, calculate the minimum amount of power needed to make 10 kg of ice.(Take latent heat for freezing as 80 kcal/kg)
Answer» A refrigerator freezes water at $0^{\circ} C$ into $10 kg$ ice at $0^{\circ} C$ in a time interval of $30 min$ . Assuming the room temperature to be $22^{\circ} C$ , calculate the minimum amount of power needed to make $10 kg$ of ice. (Take latent heat for freezing as $80 kcal/kg$ )

Discussion

3658.	36.Proton and an Alpha particle accelerated through same potential difference enter a region of uniform magnetic field with their velocities perpendicular to the field. Compare the radii of circular path followed by them if they have same Kinetic energies
Answer» 36.Proton and an Alpha particle accelerated through same potential difference enter a region of uniform magnetic field with their velocities perpendicular to the field. Compare the radii of circular path followed by them if they have same Kinetic energies

Discussion

3659.	In a diffraction pattern due to single slit of width a the first minimum is observed at an angle 30 degree when light of wavelength 5000 angstrom is incident on slit the first secondary maximum is observed at an angle of
Answer» In a diffraction pattern due to single slit of width a the first minimum is observed at an angle 30 degree when light of wavelength 5000 angstrom is incident on slit the first secondary maximum is observed at an angle of

Discussion

3660.	A square metallic wire loop of side 0.1m and resistance of 1Ω is moved with a constant velocity in a magnetic field of 2Wb-m−2 as shown in the figure. The magnetic field is perpendicular to the plane of the loop which is connected to a network of resistances. If the steady state current in the loop is 1 mA, then the velocity of loop is (in cm/sec)
Answer» A square metallic wire loop of side $0.1 m$ and resistance of $1 Ω$ is moved with a constant velocity in a magnetic field of $2 W b$ - $m^{- 2}$ as shown in the figure. The magnetic field is perpendicular to the plane of the loop which is connected to a network of resistances. If the steady state current in the loop is $1 m A$ , then the velocity of loop is (in $c m / s e c$ )

Discussion

3661.	Column I gives electrical circuits in steady state. Column II gives some statements regarding the circuits. Match appropriately (assume ammeter and voltmeter to be ideal)
Answer» Column I gives electrical circuits in steady state. Column II gives some statements regarding the circuits. Match appropriately (assume ammeter and voltmeter to be ideal)

3661.

Column I gives electrical circuits in steady state. Column II gives some statements regarding the circuits. Match appropriately (assume ammeter and voltmeter to be ideal)

Answer»

Column I gives electrical circuits in steady state. Column II gives some statements regarding the circuits. Match appropriately (assume ammeter and voltmeter to be ideal)

Discussion

3662.	Find magnetic field at the point P.
Answer» Find magnetic field at the point $P$ .

Discussion

3663.	Two small balls A and B, each of mass 'm', are attached rigidly to the ends of a light rod of length 'd'. The structure rotates about the perpendicular bisector of the rod at an angular speed ω. Calculate the angular momentum of the individual balls and of the system about the axis of rotation.
Answer» Two small balls A and B, each of mass 'm', are attached rigidly to the ends of a light rod of length 'd'. The structure rotates about the perpendicular bisector of the rod at an angular speed $ω$ . Calculate the angular momentum of the individual balls and of the system about the axis of rotation.

Discussion

3664.	Find the components along the x, y, z axes of the angular momentum l of a particle, whose position vector is r with components x, y, z and momentum is p with components px, py and pz. Show that if the particle moves only in the x-y plane the angular momentum has only a z-component.
Answer» Find the components along the x, y, z axes of the angular momentum l of a particle, whose position vector is r with components x, y, z and momentum is p with components px, py and pz. Show that if the particle moves only in the x-y plane the angular momentum has only a z-component.

Discussion

3665.	The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?
Answer» The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?

Discussion

3666.	A stone is fastened to one end of a string and is wirled in a vertical circle of radius R. Find the minimum speed the stone can have at the highest point of the circle.
Answer» A stone is fastened to one end of a string and is wirled in a vertical circle of radius R. Find the minimum speed the stone can have at the highest point of the circle.

Discussion

3667.	Values of four quantum number for the last electron ina atom are n =4, l= 1, m=+1, s=+1/2. Atomic number of the atom is?
Answer» Values of four quantum number for the last electron ina atom are n =4, l= 1, m=+1, s=+1/2. Atomic number of the atom is?

Discussion

3668.	The quantities of heat required to raise the temperature of two solid copper spheres of radii r1 and r2 (r2=1.5r1) through 1 K and 2 K respectively are in the ratio :
Answer» The quantities of heat required to raise the temperature of two solid copper spheres of radii $r_{1}$ and $r_{2} (r_{2} = 1.5 r_{1})$ through $1 K$ and $2 K$ respectively are in the ratio :

Discussion

3669.	A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of 3 × 106 ms–1. The velocity of the particle is : (mass of electron = 9.1 × 10–31 kg)Options:3 × 10–31 ms–1Wrong 2.7 × 10–21 ms–1Should have chosen 2.7 × 10–18 ms–19 × 10–2 ms–1
Answer» A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of 3 × 106 ms–1. The velocity of the particle is : (mass of electron = 9.1 × 10–31 kg) Options: 3 × 10–31 ms–1 Wrong 2.7 × 10–21 ms–1 Should have chosen 2.7 × 10–18 ms–1 9 × 10–2 ms–1

Discussion

3670.	The figure shows a wire mesh of infinite extent, such that the resistance between any two neighbouring vertices is equal. A steady current of 1A flows into the node P, from a current source, while a steady current of 1A is extracted from the node Q, as shown. Regard the situation as the superposition of two processes: the first in which the current flows into the mesh, and the second in which it flows out of the mesh. The steady current flowing in the segment PQ is equal to
Answer» The figure shows a wire mesh of infinite extent, such that the resistance between any two neighbouring vertices is equal. A steady current of 1A flows into the node P, from a current source, while a steady current of 1A is extracted from the node Q, as shown. Regard the situation as the superposition of two processes: the first in which the current flows into the mesh, and the second in which it flows out of the mesh. The steady current flowing in the segment PQ is equal to

Discussion

3671.	Two zener diodes (A and B) having breakdown voltages of 6 V and 4 V respectively are connected as shown in the circuit below. The output voltage V0 variation with input voltage linearly increasing with time, is given by:(Vinput=0 V at t=0)(figures are qualitative)
Answer» Two zener diodes ( $A$ and $B$ ) having breakdown voltages of $6 V$ and $4 V$ respectively are connected as shown in the circuit below. The output voltage $V_{0}$ variation with input voltage linearly increasing with time, is given by: ( $V_{i n p u t} = 0 V$ at $t = 0$ ) (figures are qualitative)

Discussion

3672.	The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is
Answer» The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is

3672.

The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is

Answer»

The figure shows an imaginary cube of length L/2 and a uniformly charged rod of length L touching the centre of the right face of the cube normally. At time t=0, the rod starts moving to the left slowly at a constant speed 'v'. the electric flux(F) through the cube is plotted against time(t). the correct graph showing the variation of flux with time is

Discussion

3673.	What will be the radius of 64Cu nucleus if the radius of 27Al Al nucleus is RAl ?
Answer» What will be the radius of $^{64} C u$ nucleus if the radius of $^{27} A l$ Al nucleus is $R_{A l}$ ?

Discussion

3674.	A rigid body of mass m kg is lifted with uniform velocity by a man to a height of 1 m in 30 seconds. Another man lifts the same mass with uniform velocity to the same height in 60 seconds. The work done on the body against gravity by them are in the ratio
Answer» A rigid body of mass $m kg$ is lifted with uniform velocity by a man to a height of $1 m$ in $30 seconds$ . Another man lifts the same mass with uniform velocity to the same height in $60 seconds$ . The work done on the body against gravity by them are in the ratio

Discussion

3675.	28. In a series LCR circuit, the measured value of voltage across L, C and R are 30 V, 90 V and 80 V,respectively. The supply voltage is(A) 200 V(B) 100 V(C) 140 V(D) 200 2 v
Answer» 28. In a series LCR circuit, the measured value of voltage across L, C and R are 30 V, 90 V and 80 V,respectively. The supply voltage is(A) 200 V(B) 100 V(C) 140 V(D) 200 2 v

Discussion

3676.	A particle moves a distance x in time t according to equation x = (t + 1)−3. The velocity is written in terms of distance x as where a and b are constants. Then,
Answer» A particle moves a distance x in time t according to equation x = (t + 1)−3. The velocity is written in terms of distance x as where a and b are constants. Then,

Discussion

3677.	Find the angle between the two mirrors, arranged as shown below, when the total number of images formed is seven.
Answer» Find the angle between the two mirrors, arranged as shown below, when the total number of images formed is seven.

Discussion

3678.	A 50 Hz a.c. is rectified with full wave rectifier, what is the output frequency?
Answer» A 50 Hz a.c. is rectified with full wave rectifier, what is the output frequency?

Discussion

3679.	A bullet has a mass of 0.02 kg and is movingentmewith a speed of 10 m/s. It can penetrate 10 cmof a given target before coming to rest. If thesame target is only 6 cm thick, what will be thespeed and kinetic energy of the bullet, when itcomes out the target?
Answer» A bullet has a mass of 0.02 kg and is movingentmewith a speed of 10 m/s. It can penetrate 10 cmof a given target before coming to rest. If thesame target is only 6 cm thick, what will be thespeed and kinetic energy of the bullet, when itcomes out the target?

Discussion

3680.	An insulated sphere of radius R has a volume charge density ρ . The variation of its potential with respect to the distance from the centre is best represented by
Answer» An insulated sphere of radius R has a volume charge density $ρ$ . The variation of its potential with respect to the distance from the centre is best represented by

Discussion

3681.	If →a=2^i+^j+^k,→b=^i+2^j+2^k,→c=^i+^j+2^k and →a×(→b×→c)=(1+α)^i+β(1+α)^j+γ(1+α)(1+β)^k, then the value of α−β−3γ is
Answer» If $\to a = 2^i +^j +^k, \to b =^i + 2^j + 2^k, \to c =^i +^j + 2^k$ and $\to a \times (\to b \times \to c) =$ $(1 + α)^i + β (1 + α)^j + γ (1 + α) (1 + β)^k$ , then the value of $α - β - 3 γ$ is

Discussion

3682.	The absolute temperature of air in a region linearly increases from T1, to T2, in a space of width d. Find the time taken by a sound wave to go through the region in terms of T1T2, d and the speed u of sound at 273 K. Evaluate this time for T1≈280K,T3=310K, d = 33 m and v=330ms−1.
Answer» The absolute temperature of air in a region linearly increases from $T_{1}$ , to $T_{2}$ , in a space of width d. Find the time taken by a sound wave to go through the region in terms of $T_{1} T_{2}$ , d and the speed u of sound at 273 K. Evaluate this time for $T_{1} \approx 280 K, T_{3} = 310 K$ , d = 33 m and $v = 330 m s^{- 1}$ .

Discussion

3683.	A force (mv^2/r) is acting on a body of mass m moving with a velocity v ina circle of radius r. what is the work done by the force in moving the body over half the circumference of the circle?
Answer» A force (mv^2/r) is acting on a body of mass m moving with a velocity v ina circle of radius r. what is the work done by the force in moving the body over half the circumference of the circle?

Discussion

3684.	If the radius of earth and acceleration due to gravity on surface both are doubled, escape velocity of a satellite from surface of earth will become
Answer» If the radius of earth and acceleration due to gravity on surface both are doubled, escape velocity of a satellite from surface of earth will become

Discussion

3685.	A simple pendulum with iron bob has a time period T. The bob is now immersed in a non-viscous liquid and oscillated. If the density of liquid is th that of iron, then new time period will be
Answer» A simple pendulum with iron bob has a time period T. The bob is now immersed in a non-viscous liquid and oscillated. If the density of liquid is th that of iron, then new time period will be

Discussion

3686.	A granite rod of 60 cm length is clamped at its middle point and is set into longitudinal vibrations. The density of granite is 2.7×103 kg/m3 and its Young's modulus is 9.27×1010 Pa. What will be the fundamental frequency of the longitudinal vibrations?
Answer» A granite rod of $60 c m$ length is clamped at its middle point and is set into longitudinal vibrations. The density of granite is $2.7 \times 10^{3} k g / m^{3}$ and its Young's modulus is $9.27 \times 10^{10} P a$ . What will be the fundamental frequency of the longitudinal vibrations?

Discussion

3687.	The current in a circuit varies with time as I=2\surd t. Then the rms value of the current for interval t=2 to t=4 sec is (1)\surd3 A (2)2\surd3 A (3)\surd3/2 A (4) (4-2\surd2)
Answer» The current in a circuit varies with time as I=2\surd t. Then the rms value of the current for interval t=2 to t=4 sec is (1)\surd3 A (2)2\surd3 A (3)\surd3/2 A (4) (4-2\surd2)

Discussion

3688.	The magnitude of scalar product of two vectors is 8 and that of vector product is 8√3. The angle between them is
Answer» The magnitude of scalar product of two vectors is 8 and that of vector product is $8 \sqrt{3}$ . The angle between them is

Discussion

3689.	A 50 W, 100 V lamp is to be connected to an AC mains of 200 V,50 Hz. What capacitance is essential to be put in series with the lamp?
Answer» A $50 W, 100 V$ lamp is to be connected to an $A C$ mains of $200 V, 50 Hz$ . What capacitance is essential to be put in series with the lamp?

Discussion

3690.	A ball of 200g falls from a height of 5metre .What is the kinetic energy when it reaches the ground.assume g=9.8m/s
Answer» A ball of 200g falls from a height of 5metre .What is the kinetic energy when it reaches the ground.assume g=9.8m/s

Discussion

3691.	Calculate the work done by an ideal gas as it is taken through the process (1 - 2 - 3) as shown in the graph below.
Answer» Calculate the work done by an ideal gas as it is taken through the process (1 - 2 - 3) as shown in the graph below.

3691.

Calculate the work done by an ideal gas as it is taken through the process (1 - 2 - 3) as shown in the graph below.

Answer»

Calculate the work done by an ideal gas as it is taken through the process (1 - 2 - 3) as shown in the graph below.

Discussion

3692.	67.If all the the particles of a body is situated at distanced from origin, then the distance of C.M. of the body from origin is. greater than or equal to d . Why
Answer» 67.If all the the particles of a body is situated at distanced from origin, then the distance of C.M. of the body from origin is. greater than or equal to d . Why

Discussion

3693.	30. What are induced radiations and how to calculate them
Answer» 30. What are induced radiations and how to calculate them

Discussion

3694.	A uniform rod AB,4m long and weight 12kg, is supported at end A, with a 6kg lead weight at B. The rod floats as shown in figure with one-half of its length submerged. The buoyant force on the lead mass is negligible as it is of negligible volume. Find the tension in the cord and the total volume of the rod.
Answer» A uniform rod $AB, 4 m$ long and weight $12 kg$ , is supported at end A, with a $6 kg$ lead weight at B. The rod floats as shown in figure with one-half of its length submerged. The buoyant force on the lead mass is negligible as it is of negligible volume. Find the tension in the cord and the total volume of the rod.

Discussion

3695.	A charged particle having drift velocity of 7.5×10−4 ms−1 in an electric field of 3×10−10 Vm−1 has a mobility in m2V−1s−1 of?
Answer» A charged particle having drift velocity of $7.5 \times 10^{- 4} {ms}^{- 1}$ in an electric field of $3 \times 10^{- 10} {Vm}^{- 1}$ has a mobility in $m^{2} V^{- 1} s^{- 1}$ of?

Discussion

3696.	A ball is thrown vertically upward from the top of a tower. Velocity at depth h from the point of projection is twice of the velocity at height h above the point of projection. Find the maximum height reached by the ball.
Answer» A ball is thrown vertically upward from the top of a tower. Velocity at depth $h$ from the point of projection is twice of the velocity at height $h$ above the point of projection. Find the maximum height reached by the ball.

Discussion

3697.	The area A of a circle is related to its diameter by the equation A=π4D2. The change in area with respect to the diameter is x×π, when the diameter is 10 m. Find the value of x.
Answer» The area $A$ of a circle is related to its diameter by the equation $A = \frac{π}{4} D^{2}$ . The change in area with respect to the diameter is $x \times π$ , when the diameter is $10 m$ . Find the value of $x$ .

Discussion

3698.	Find the natural frequency of oscillation of the system shown in the figure. Pulleys are massless and frictionless. Spring and strings are also massless.
Answer» Find the natural frequency of oscillation of the system shown in the figure. Pulleys are massless and frictionless. Spring and strings are also massless.

Discussion

3699.	A body is dropped from a height of 39.2 m. After it crosses the half distance, the acceleration due to gravity comes to an end. Then the body will hit the ground with a velocity of (Take g=9.8 ms−2)
Answer» A body is dropped from a height of $39.2 m$ . After it crosses the half distance, the acceleration due to gravity comes to an end. Then the body will hit the ground with a velocity of $($ Take $g = 9.8 {ms}^{- 2})$

Discussion

3700.	The angular velocity of a cycle wheel is 10 rads/s. If the diameter of the wheel is 80 cm, then find the speed of the cycle in m/s unit. Explain it by doing the sum.
Answer» The angular velocity of a cycle wheel is 10 rads/s. If the diameter of the wheel is 80 cm, then find the speed of the cycle in m/s unit. Explain it by doing the sum.

Discussion

Explore topic-wise InterviewSolutions in .

A river is flowing with a speed of 1 kmh−1. A swimmer wants to go to point C starting form A. He swims with a speed of 5 kmh−1 at an angle θ with the river flow. If AB=BC=400 m, at what angle with the river bank should the swimmer swim?

A force acting on body of 1 tonne at rest. The body acquired a velocity of 1ms`1 in a distance of 10m.find the force

A square of side 2 m is placed in a uniform magnetic field B=2 T in a direction perpendicular to the plane of square and pointing inwards Equal current i=3 A is flowing in the direction shown in figure. The magnitude of magnetic force acting on the loop will be :

A semiconductor is known to have an electron concentration of 8×1013/cc and hole concentration of 5×1012/cc . The semiconductor is

Find the number of moles of oxygen atoms present in 1.2×1026 atoms of oxygen. (Given: NA=6×1023)

A refrigerator freezes water at 0∘C into 10 kg ice at 0∘C in a time interval of 30 min. Assuming the room temperature to be 22∘C, calculate the minimum amount of power needed to make 10 kg of ice.(Take latent heat for freezing as 80 kcal/kg)

36.Proton and an Alpha particle accelerated through same potential difference enter a region of uniform magnetic field with their velocities perpendicular to the field. Compare the radii of circular path followed by them if they have same Kinetic energies

In a diffraction pattern due to single slit of width a the first minimum is observed at an angle 30 degree when light of wavelength 5000 angstrom is incident on slit the first secondary maximum is observed at an angle of

Column I gives electrical circuits in steady state. Column II gives some statements regarding the circuits. Match appropriately (assume ammeter and voltmeter to be ideal)

Find magnetic field at the point P.

Two small balls A and B, each of mass 'm', are attached rigidly to the ends of a light rod of length 'd'. The structure rotates about the perpendicular bisector of the rod at an angular speed ω. Calculate the angular momentum of the individual balls and of the system about the axis of rotation.

Find the components along the x, y, z axes of the angular momentum l of a particle, whose position vector is r with components x, y, z and momentum is p with components px, py and pz. Show that if the particle moves only in the x-y plane the angular momentum has only a z-component.

The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelength 330 nm?

A stone is fastened to one end of a string and is wirled in a vertical circle of radius R. Find the minimum speed the stone can have at the highest point of the circle.

Values of four quantum number for the last electron ina atom are n =4, l= 1, m=+1, s=+1/2. Atomic number of the atom is?

The quantities of heat required to raise the temperature of two solid copper spheres of radii r1 and r2 (r2=1.5r1) through 1 K and 2 K respectively are in the ratio :

A particle of mass 1 mg has the same wavelength as an electron moving with a velocity of 3 × 106 ms–1. The velocity of the particle is : (mass of electron = 9.1 × 10–31 kg)Options:3 × 10–31 ms–1Wrong 2.7 × 10–21 ms–1Should have chosen 2.7 × 10–18 ms–19 × 10–2 ms–1

Two zener diodes (A and B) having breakdown voltages of 6 V and 4 V respectively are connected as shown in the circuit below. The output voltage V0 variation with input voltage linearly increasing with time, is given by:(Vinput=0 V at t=0)(figures are qualitative)

What will be the radius of 64Cu nucleus if the radius of 27Al Al nucleus is RAl ?

A rigid body of mass m kg is lifted with uniform velocity by a man to a height of 1 m in 30 seconds. Another man lifts the same mass with uniform velocity to the same height in 60 seconds. The work done on the body against gravity by them are in the ratio

28. In a series LCR circuit, the measured value of voltage across L, C and R are 30 V, 90 V and 80 V,respectively. The supply voltage is(A) 200 V(B) 100 V(C) 140 V(D) 200 2 v

A particle moves a distance x in time t according to equation x = (t + 1)−3. The velocity is written in terms of distance x as where a and b are constants. Then,

Find the angle between the two mirrors, arranged as shown below, when the total number of images formed is seven.

A 50 Hz a.c. is rectified with full wave rectifier, what is the output frequency?

A bullet has a mass of 0.02 kg and is movingentmewith a speed of 10 m/s. It can penetrate 10 cmof a given target before coming to rest. If thesame target is only 6 cm thick, what will be thespeed and kinetic energy of the bullet, when itcomes out the target?

An insulated sphere of radius R has a volume charge density ρ . The variation of its potential with respect to the distance from the centre is best represented by

If →a=2^i+^j+^k,→b=^i+2^j+2^k,→c=^i+^j+2^k and →a×(→b×→c)=(1+α)^i+β(1+α)^j+γ(1+α)(1+β)^k, then the value of α−β−3γ is

The absolute temperature of air in a region linearly increases from T1, to T2, in a space of width d. Find the time taken by a sound wave to go through the region in terms of T1T2, d and the speed u of sound at 273 K. Evaluate this time for T1≈280K,T3=310K, d = 33 m and v=330ms−1.

A force (mv^2/r) is acting on a body of mass m moving with a velocity v ina circle of radius r. what is the work done by the force in moving the body over half the circumference of the circle?

If the radius of earth and acceleration due to gravity on surface both are doubled, escape velocity of a satellite from surface of earth will become

A simple pendulum with iron bob has a time period T. The bob is now immersed in a non-viscous liquid and oscillated. If the density of liquid is th that of iron, then new time period will be

A granite rod of 60 cm length is clamped at its middle point and is set into longitudinal vibrations. The density of granite is 2.7×103 kg/m3 and its Young's modulus is 9.27×1010 Pa. What will be the fundamental frequency of the longitudinal vibrations?

The current in a circuit varies with time as I=2\surd t. Then the rms value of the current for interval t=2 to t=4 sec is (1)\surd3 A (2)2\surd3 A (3)\surd3/2 A (4) (4-2\surd2)

The magnitude of scalar product of two vectors is 8 and that of vector product is 8√3. The angle between them is

A 50 W, 100 V lamp is to be connected to an AC mains of 200 V,50 Hz. What capacitance is essential to be put in series with the lamp?

A ball of 200g falls from a height of 5metre .What is the kinetic energy when it reaches the ground.assume g=9.8m/s

Calculate the work done by an ideal gas as it is taken through the process (1 - 2 - 3) as shown in the graph below.

67.If all the the particles of a body is situated at distanced from origin, then the distance of C.M. of the body from origin is. greater than or equal to d . Why

30. What are induced radiations and how to calculate them

A charged particle having drift velocity of 7.5×10−4 ms−1 in an electric field of 3×10−10 Vm−1 has a mobility in m2V−1s−1 of?

A ball is thrown vertically upward from the top of a tower. Velocity at depth h from the point of projection is twice of the velocity at height h above the point of projection. Find the maximum height reached by the ball.

The area A of a circle is related to its diameter by the equation A=π4D2. The change in area with respect to the diameter is x×π, when the diameter is 10 m. Find the value of x.

Find the natural frequency of oscillation of the system shown in the figure. Pulleys are massless and frictionless. Spring and strings are also massless.

A body is dropped from a height of 39.2 m. After it crosses the half distance, the acceleration due to gravity comes to an end. Then the body will hit the ground with a velocity of (Take g=9.8 ms−2)

The angular velocity of a cycle wheel is 10 rads/s. If the diameter of the wheel is 80 cm, then find the speed of the cycle in m/s unit. Explain it by doing the sum.