50278 + Interview Questions in Physics Page 136 InterviewSolution

6751.	A wheel with 10 metallic spokes each 0.5mHong is rotated with a speed of 120 rev/min in a planenormal to the earth's magnetic field at the place. Ifhe magnitude of the field is 0.4 G, the induced e.m.f.petween the axle and the rim of the wheel equal to1) 1.256 x 10-3 V2) 6.28 x 10-4 V3) 1.256 x 104 V4) 6.28 x 10-5 V
Answer» A wheel with 10 metallic spokes each 0.5mHong is rotated with a speed of 120 rev/min in a planenormal to the earth's magnetic field at the place. Ifhe magnitude of the field is 0.4 G, the induced e.m.f.petween the axle and the rim of the wheel equal to1) 1.256 x 10-3 V2) 6.28 x 10-4 V3) 1.256 x 104 V4) 6.28 x 10-5 V

Discussion

6752.	A ball is projected from ground with speed 10 m/s, then the minimum angle of projection so that the ball lands on the 2nd stair is
Answer» A ball is projected from ground with speed 10 m/s, then the minimum angle of projection so that the ball lands on the 2nd stair is

Discussion

6753.	The load versus elongation graph of four wires of equal length of the same material is shown in the figure. The line representing the thinnest wire is
Answer» The load versus elongation graph of four wires of equal length of the same material is shown in the figure. The line representing the thinnest wire is

Discussion

6754.	A bullet of mass 50 g moving with a speed of 500 m/s brought to rest in 0.01 seconds .Find the impulse and the average force ?
Answer» A bullet of mass 50 g moving with a speed of 500 m/s brought to rest in 0.01 seconds .Find the impulse and the average force ?

Discussion

6755.	For an observer on trolley, the direction of projection of particle is shown in figure, while for observer on ground ball rises vertically. Maximum height (in meter) seen from the trolley is: (take g=10 ms−2)
Answer» For an observer on trolley, the direction of projection of particle is shown in figure, while for observer on ground ball rises vertically. Maximum height (in meter) seen from the trolley is: (take $g = 10 {ms}^{- 2}$ )

Discussion

6756.	A coil of inductance 200 H and resistance 20Ω is connected to a constant voltage source. How soon in seconds will the coil current reach 50% of the steady state value?(ln2 = 0.693). Write upto two digits after the decimal point.
Answer» A coil of inductance 200 H and resistance $20 Ω$ is connected to a constant voltage source. How soon in seconds will the coil current reach 50% of the steady state value?(ln2 = 0.693). Write upto two digits after the decimal point.

Discussion

6757.	A body starts from rest and travels s m in 2nd second, then, acceleration is
Answer» A body starts from rest and travels $s m$ in $2^{n d}$ second, then, acceleration is

Discussion

6758.	ABC is an equilateral triangle of side 2 m. If electric field E=10 NC−1 then the potential difference VA−VB is
Answer» $ABC$ is an equilateral triangle of side $2 m$ . If electric field $E = 10 {NC}^{- 1}$ then the potential difference $V_{A} - V_{B}$ is

Discussion

6759.	We wish to see inside the atom. Assuming the atom to have a diameter of 100 pm, this means that one must be able to resolve a width of say 10 pm. If an electron-micro scope is used, the minimum electron energy required is about. (Assume the wavelength of light used in an electron microscope is nearly equal to the resolving power of the electron microscope.)
Answer» We wish to see inside the atom. Assuming the atom to have a diameter of $100 pm$ , this means that one must be able to resolve a width of say $10 pm$ . If an electron-micro scope is used, the minimum electron energy required is about. (Assume the wavelength of light used in an electron microscope is nearly equal to the resolving power of the electron microscope.)

Discussion

6760.	The string of a simple pendulum in attached with the ceiling of a car moving on a straight horizontal road with an acceleration a = g÷\sqrt{3 }, where g is acceleration due to gravity near earth surface. The pendulum is made to oscillate at an angular amplitude of 30 degree If the tension in the string is maximum when the string makes an angle theta with the vertical,then value of theta i
Answer» The string of a simple pendulum in attached with the ceiling of a car moving on a straight horizontal road with an acceleration a = g÷\sqrt{3 }, where g is acceleration due to gravity near earth surface. The pendulum is made to oscillate at an angular amplitude of 30 degree If the tension in the string is maximum when the string makes an angle theta with the vertical,then value of theta i

Discussion

6761.	nta boy moves 400m towards north, 300m towards west and again 400m towards south.n ntcalculate the displacement of the boy from initial positionn
Answer» nta boy moves 400m towards north, 300m towards west and again 400m towards south.n ntcalculate the displacement of the boy from initial positionn

Discussion

6762.	A box of mass 2 kg slides from a height of 8 m on the inclined plane and struck the ball. After collision, the ball sticks on the box. If mass of the ball is 200 g, then what will be the velocity of the box after collision? Assuming all surfaces are frictionless and initially the ball is at rest. (take g=10m/s2)
Answer» A box of mass $2 kg$ slides from a height of $8 m$ on the inclined plane and struck the ball. After collision, the ball sticks on the box. If mass of the ball is $200 g$ , then what will be the velocity of the box after collision? Assuming all surfaces are frictionless and initially the ball is at rest. (take $g = 10 m / s^{2})$

Discussion

6763.	Figures9.34(a) and (b) show refraction of a ray in air incident at 60°with the normal to a glass-air and water-air interface, respectively.Predict the angle of refraction in glass when the angle of incidencein water is 45º with the normal to a water-glass interface [Fig.9.34(c)].
Answer» Figures 9.34(a) and (b) show refraction of a ray in air incident at 60° with the normal to a glass-air and water-air interface, respectively. Predict the angle of refraction in glass when the angle of incidence in water is 45º with the normal to a water-glass interface [Fig. 9.34(c)].

6763.

Figures9.34(a) and (b) show refraction of a ray in air incident at 60°with the normal to a glass-air and water-air interface, respectively.Predict the angle of refraction in glass when the angle of incidencein water is 45º with the normal to a water-glass interface [Fig.9.34(c)].

Answer»

Figures
9.34(a) and (b) show refraction of a ray in air incident at 60°
with the normal to a glass-air and water-air interface, respectively.
Predict the angle of refraction in glass when the angle of incidence
in water is 45º with the normal to a water-glass interface [Fig.
9.34(c)].

Discussion

6764.	When an electron in hydrogen atom is excited, from its 4th to 5th stationary orbit, the change in angular momentum of electron is (Planck’s constant:h=6.6×10−34J−s)
Answer» When an electron in hydrogen atom is excited, from its $4^{t h}$ to $5^{t h}$ stationary orbit, the change in angular momentum of electron is (Planck’s constant: $h = 6.6 \times 10^{- 34} J - s$ )

Discussion

6765.	The displacement equation of a particle is x=[3sin(4t)+4sin(4t)] cm . The amplitude and maximum speed of the particle during oscillation will be
Answer» The displacement equation of a particle is $x = [3 sin (4 t) + 4 sin (4 t)] c m$ . The amplitude and maximum speed of the particle during oscillation will be

Discussion

6766.	Force between two charges placed at a distance r in vacuum is F .Now a dielectric slab of K =4 is inserted between them .its thickness is r/2.The new force between the charges F/4 F/2. 3F/5. 4F/9.
Answer» Force between two charges placed at a distance r in vacuum is F .Now a dielectric slab of K =4 is inserted between them .its thickness is r/2.The new force between the charges F/4 F/2. 3F/5. 4F/9.

Discussion

6767.	which combination give electrovalent bond- 1 P and Cl 2 H and Ca 3 NH_{3 } and BH_3 4 H and S
Answer» which combination give electrovalent bond- 1 P and Cl 2 H and Ca 3 NH_{3 } and BH_3 4 H and S

Discussion

6768.	26.a ball is projected from the ground . It just touches the top of 6m high wall at a distance of 4m and strikes the ground 8m behind the wall. calculate the angle of projection and velocity of projection Click here to view details:
Answer» 26.a ball is projected from the ground . It just touches the top of 6m high wall at a distance of 4m and strikes the ground 8m behind the wall. calculate the angle of projection and velocity of projection Click here to view details:

Discussion

6769.	Let n>2 be an integer. Suppose that there are n Metro stations in a city located along circular path. Each pair of stations is connected by a stright track only. Further, each pair of nearest stations is connected by blue line, whereas all remaining pairs of stations are connected by red line. If the number of red lines is 99 times the number of blue lines, then the value of n is:
Answer» Let $n > 2$ be an integer. Suppose that there are $n$ Metro stations in a city located along circular path. Each pair of stations is connected by a stright track only. Further, each pair of nearest stations is connected by blue line, whereas all remaining pairs of stations are connected by red line. If the number of red lines is $99$ times the number of blue lines, then the value of $n$ is:

Discussion

6770.	A potentiometer wire has length 4 m and resistance 8 Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm on the wire is :
Answer» A potentiometer wire has length 4 m and resistance 8 Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm on the wire is :

6770.

A potentiometer wire has length 4 m and resistance 8 Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm on the wire is :

Answer»

A potentiometer wire has length 4 m and resistance 8 Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm on the wire is :

Discussion

6771.	A ray of light falls on a plane mirror. When the mirror is turned clockwise about an axis along the plane of the mirror by 20∘, the incident ray gets deflected by 45∘. The original incidence angle is
Answer» A ray of light falls on a plane mirror. When the mirror is turned clockwise about an axis along the plane of the mirror by $20^{\circ}$ , the incident ray gets deflected by $45^{\circ}$ . The original incidence angle is

Discussion

6772.	The magnitude of force is member EF for frame shown below will be
Answer» The magnitude of force is member EF for frame shown below will be

Discussion

6773.	Find the velocity of the hanging block if the velocities of the free ends of the rope are as indicated in the figure. Take the upward velocity to be positive.
Answer» Find the velocity of the hanging block if the velocities of the free ends of the rope are as indicated in the figure. Take the upward velocity to be positive.

Discussion

6774.	Two wires of same lenth are shaped into a square and a circle. If they carry same current then the ratio of magnetic field intensity at centres of square and circle respectively is
Answer» Two wires of same lenth are shaped into a square and a circle. If they carry same current then the ratio of magnetic field intensity at centres of square and circle respectively is

Discussion

6775.	Two parallel plane sheets 1 and 2 carry uniform charge densities σ1 and σ2 (see Fig. 20.8). The electric field in the region marked I is (σ1>σ2). (Consider the right direction as the positive direction)
Answer» Two parallel plane sheets 1 and 2 carry uniform charge densities $σ_{1}$ and $σ_{2}$ (see Fig. 20.8). The electric field in the region marked I is $(σ_{1} > σ_{2})$ . (Consider the right direction as the positive direction)

Discussion

6776.	A scooter starting from rest moves with a constant acceleration for a time Δ t1, then with a constant velocity for the next Δ t2, and finally with a constant deceleration. A person of mass 50 kg on the scooter, behind the driver manages to stay at rest with respect to the scooter without touching any other part. The force exerted by the seat on the man is Take g=10m/ s2
Answer» A scooter starting from rest moves with a constant acceleration for a time $Δ$ $t_{1}$ , then with a constant velocity for the next $Δ$ $t_{2}$ , and finally with a constant deceleration. A person of mass 50 kg on the scooter, behind the driver manages to stay at rest with respect to the scooter without touching any other part. The force exerted by the seat on the man is Take g=10m/ $s^{2}$

6776.

A scooter starting from rest moves with a constant acceleration for a time Δ t1, then with a constant velocity for the next Δ t2, and finally with a constant deceleration. A person of mass 50 kg on the scooter, behind the driver manages to stay at rest with respect to the scooter without touching any other part. The force exerted by the seat on the man is Take g=10m/ s2

Answer»

A scooter starting from rest moves with a constant acceleration for a time $Δ$ $t_{1}$ , then with a constant velocity for the next $Δ$ $t_{2}$ , and finally with a constant deceleration. A person of mass 50 kg on the scooter, behind the driver manages to stay at rest with respect to the scooter without touching any other part. The force exerted by the seat on the man is

Take g=10m/ $s^{2}$

Discussion

6777.	An electron of mass m=9.1×10−31 kg charge q=−1.6×10−19 C experiences no deflection , if subjected to an electric field of E=3.2×105 V/m and a magnetic field of B=2.0×10−3 Wb/m2. Both the fields are normal to the path of electron and to each other. If the electric field is removed, then the electron will revolve in an orbit of radius ?
Answer» An electron of mass $m = 9.1 \times 10^{- 31} kg$ charge $q = - 1.6 \times 10^{- 19} C$ experiences no deflection , if subjected to an electric field of $E = 3.2 \times 10^{5} V / m$ and a magnetic field of $B = 2.0 \times 10^{- 3} Wb / m^{2}$ . Both the fields are normal to the path of electron and to each other. If the electric field is removed, then the electron will revolve in an orbit of radius ?

Discussion

6778.	A ladder AB of length 5 m and weight (W) 600 N is resting against a wall. Assuming frictionless contact at the floor (B) and the wall (A), the magnitude of the force P (in newton) required to maintain equilibrium of the ladder is
Answer» A ladder AB of length 5 m and weight (W) 600 N is resting against a wall. Assuming frictionless contact at the floor (B) and the wall (A), the magnitude of the force P (in newton) required to maintain equilibrium of the ladder is

Discussion

6779.	Two plane mirrors are inclined at angle θ as shown in figure. If a ray parallel to OB strikes the other mirror at P and finally emerges parallel to OA after two reflections, then θ is equal to
Answer» Two plane mirrors are inclined at angle $θ$ as shown in figure. If a ray parallel to $O B$ strikes the other mirror at $P$ and finally emerges parallel to $O A$ after two reflections, then $θ$ is equal to

Discussion

6780.	Two moles of an ideal monoatomic gas at 27∘C occupies a volume of V. If the gas is expanded adiabatically to the volume 23/2V, then the work done by the gas will be (γ=53,R=8.31 J/mol K)
Answer» Two $moles$ of an ideal monoatomic gas at $27^{\circ} C$ occupies a volume of $V$ . If the gas is expanded adiabatically to the volume $2^{3 / 2} V$ , then the work done by the gas will be $(γ = \frac{5}{3}, R = 8.31 J/mol K)$

Discussion

6781.	Uranium ores contain one radium −226 atoms for every 2.8×106 uranium −238 atoms. Calculate the half - life of 23892U, given that the half - life of 22688Ra is 1600 years. (22688Ra is a decay product of 23892U)
Answer» Uranium ores contain one radium $- 226$ atoms for every $2.8 \times 10^{6}$ uranium $- 238$ atoms. Calculate the half - life of $_{92}^{238} U$ , given that the half - life of $_{88}^{226} R a$ is 1600 years. ( $_{88}^{226} R a$ is a decay product of $_{92}^{238} U$ )

Discussion

6782.	Find at what depth of a pond the total pressure will be 1.5 times of the atmospheric pressure.
Answer» Find at what depth of a pond the total pressure will be 1.5 times of the atmospheric pressure.

Discussion

6783.	The ratio of electric potential on a equatorial and a axial point of short dipole will be 1 0
Answer» The ratio of electric potential on a equatorial and a axial point of short dipole will be 1 0

Discussion

6784.	The wavelength of the matter wave is independent of
Answer» The wavelength of the matter wave is independent of

Discussion

6785.	Will the average and instantaneous acceleration of the body vary of the object changes its direction of velocity or has a turning point .
Answer» Will the average and instantaneous acceleration of the body vary of the object changes its direction of velocity or has a turning point .

Discussion

6786.	The velocity of a particle is v=v0+gt+ft2. If its position is x=0 at t=0, then its displacement after unit time (t=1) is
Answer» The velocity of a particle is $v = v_{0} + g t + f t^{2}$ . If its position is $x = 0$ at $t = 0$ , then its displacement after unit time $(t = 1)$ is

Discussion

6787.	A vector of length l is turned through the angle θ about its tail. What is the change in the position vector of its head?why should we take 180 -theta and why not 60 degree?when should we use phi value instead of theta?
Answer» A vector of length l is turned through the angle θ about its tail. What is the change in the position vector of its head? why should we take 180 -theta and why not 60 degree? when should we use phi value instead of theta?

Discussion

6788.	A stationary person observes that rain is falling vertically down at 18 km/hr. A cyclist is moving in positive x- direction on the level road, at 24 km/hr. At what angle from the horizontal should the cyclist hold his umbrella to protect himself from rain?
Answer» A stationary person observes that rain is falling vertically down at $18 km/hr$ . A cyclist is moving in positive x- direction on the level road, at $24 km/hr$ . At what angle from the horizontal should the cyclist hold his umbrella to protect himself from rain?

Discussion

6789.	A block of mass 15 kg is placed on a long trolley. The coefficient of static friction between the block and the trolley is 0.18. The trolley accelerates from rest with 0.5 m s–2 for 20 s and then moves with uniform velocity. Discuss the motion of the block as viewed by (a) a stationary observer on the ground, (b) an observer moving with the trolley.
Answer» A block of mass 15 kg is placed on a long trolley. The coefficient of static friction between the block and the trolley is 0.18. The trolley accelerates from rest with 0.5 m s^–2 for 20 s and then moves with uniform velocity. Discuss the motion of the block as viewed by (a) a stationary observer on the ground, (b) an observer moving with the trolley.

Discussion

6790.	Power Dilivered to an object of mass M is P. Velocity of object at time T is V .If it will start from rest then Calaulate power dilivered ty engine in time 't'
Answer» Power Dilivered to an object of mass M is P. Velocity of object at time T is V .If it will start from rest then Calaulate power dilivered ty engine in time 't'

Discussion

6791.	Potential energy U(x) and associated force F(x) bear the relation F(x)=−dU(x)dx. Dependence of potential energy of a two-particle system on the separation x between them is shown in the following figure. Which of the following graphs shows the correct variation of force F(x) with x?
Answer» Potential energy $U (x)$ and associated force $F (x)$ bear the relation $F (x) = \frac{- d U (x)}{d x}$ . Dependence of potential energy of a two-particle system on the separation $x$ between them is shown in the following figure. Which of the following graphs shows the correct variation of force $F (x)$ with $x$ ?

Discussion

6792.	The magnetic flux linked with a coil is given by the equation ϕ=2t2−8t+16. what will be the magnitude of flux linked with the coil, when induced emf in the coil is zero?
Answer» The magnetic flux linked with a coil is given by the equation $ϕ = 2 t^{2} - 8 t + 16$ . what will be the magnitude of flux linked with the coil, when induced emf in the coil is zero?

Discussion

6793.	Burst the bubbles whose derivative is a straight line.
Answer» Burst the bubbles whose derivative is a straight line.

Discussion

6794.	Aprism is made of glass of unknown refractive index. A parallelbeam of light is incident on a face of the prism. The angle ofminimum deviation is measured to be 40°. What is the refractiveindex of the material of the prism? The refracting angle of the prismis 60°. If the prism is placed in water (refractive index 1.33),predict the new angle of minimum deviation of a parallel beam oflight.
Answer» A prism is made of glass of unknown refractive index. A parallel beam of light is incident on a face of the prism. The angle of minimum deviation is measured to be 40°. What is the refractive index of the material of the prism? The refracting angle of the prism is 60°. If the prism is placed in water (refractive index 1.33), predict the new angle of minimum deviation of a parallel beam of light.

Discussion

6795.	What were the observations that made us look for the existence of neutrons?
Answer» What were the observations that made us look for the existence of neutrons?

Discussion

6796.	The charge per unit length of the four quadrant of the ring is 2λ, −2λ, λ and −λ respectively. Find the electric field at the centre.
Answer» The charge per unit length of the four quadrant of the ring is $2 λ, - 2 λ, λ$ and $- λ$ respectively. Find the electric field at the centre.

Discussion

6797.	A solid cylinder of mass m and radius r starts rolling down on inclined plane of inclination θ. Friction is sufficient enough to prevent slipping. Find the speed of centre of mass of solid cylinder, when it's centre of mass has fallen through a height of h=9 m. (Take g=10 m/s2)
Answer» A solid cylinder of mass $m$ and radius $r$ starts rolling down on inclined plane of inclination $θ$ . Friction is sufficient enough to prevent slipping. Find the speed of centre of mass of solid cylinder, when it's centre of mass has fallen through a height of $h = 9 m$ . (Take $g = 10 {m/s}^{2}$ )

Discussion

6798.	What is the value of linear velocity, if →ω=3^i−4^j+^k and →r=5^i−6^j+6^k
Answer» What is the value of linear velocity, if $\to ω = 3^i - 4^j +^k$ and $\to r = 5^i - 6^j + 6^k$

Discussion

6799.	A conducting rod of length l is hinged at point O. It is free to rotate in a vertical plane. The rod is released from the position shown. The potential difference between the two ends of the rod is proportional to
Answer» A conducting rod of length $l$ is hinged at point $O$ . It is free to rotate in a vertical plane. The rod is released from the position shown. The potential difference between the two ends of the rod is proportional to

Discussion

6800.	What physical quantity is the same for X-rays of wavelength10–10 m, red light of wavelength 6800 Å and radiowaves of wavelength 500m?
Answer» What physical quantity is the same for X-rays of wavelength10–10 m, red light of wavelength 6800 Å and radiowaves of wavelength 500m?

Discussion

Explore topic-wise InterviewSolutions in .

A ball is projected from ground with speed 10 m/s, then the minimum angle of projection so that the ball lands on the 2nd stair is

The load versus elongation graph of four wires of equal length of the same material is shown in the figure. The line representing the thinnest wire is

A bullet of mass 50 g moving with a speed of 500 m/s brought to rest in 0.01 seconds .Find the impulse and the average force ?

For an observer on trolley, the direction of projection of particle is shown in figure, while for observer on ground ball rises vertically. Maximum height (in meter) seen from the trolley is: (take g=10 ms−2)

A coil of inductance 200 H and resistance 20Ω is connected to a constant voltage source. How soon in seconds will the coil current reach 50% of the steady state value?(ln2 = 0.693). Write upto two digits after the decimal point.

A body starts from rest and travels s m in 2nd second, then, acceleration is

ABC is an equilateral triangle of side 2 m. If electric field E=10 NC−1 then the potential difference VA−VB is

nta boy moves 400m towards north, 300m towards west and again 400m towards south.n ntcalculate the displacement of the boy from initial positionn

Figures9.34(a) and (b) show refraction of a ray in air incident at 60°with the normal to a glass-air and water-air interface, respectively.Predict the angle of refraction in glass when the angle of incidencein water is 45º with the normal to a water-glass interface [Fig.9.34(c)].

When an electron in hydrogen atom is excited, from its 4th to 5th stationary orbit, the change in angular momentum of electron is (Planck’s constant:h=6.6×10−34J−s)

The displacement equation of a particle is x=[3sin(4t)+4sin(4t)] cm . The amplitude and maximum speed of the particle during oscillation will be

Force between two charges placed at a distance r in vacuum is F .Now a dielectric slab of K =4 is inserted between them .its thickness is r/2.The new force between the charges F/4 F/2. 3F/5. 4F/9.

which combination give electrovalent bond- 1 P and Cl 2 H and Ca 3 NH_{3 } and BH_3 4 H and S

26.a ball is projected from the ground . It just touches the top of 6m high wall at a distance of 4m and strikes the ground 8m behind the wall. calculate the angle of projection and velocity of projection Click here to view details:

A potentiometer wire has length 4 m and resistance 8 Ω. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm on the wire is :

A ray of light falls on a plane mirror. When the mirror is turned clockwise about an axis along the plane of the mirror by 20∘, the incident ray gets deflected by 45∘. The original incidence angle is

The magnitude of force is member EF for frame shown below will be

Find the velocity of the hanging block if the velocities of the free ends of the rope are as indicated in the figure. Take the upward velocity to be positive.

Two wires of same lenth are shaped into a square and a circle. If they carry same current then the ratio of magnetic field intensity at centres of square and circle respectively is

Two parallel plane sheets 1 and 2 carry uniform charge densities σ1 and σ2 (see Fig. 20.8). The electric field in the region marked I is (σ1&gt;σ2). (Consider the right direction as the positive direction)

A ladder AB of length 5 m and weight (W) 600 N is resting against a wall. Assuming frictionless contact at the floor (B) and the wall (A), the magnitude of the force P (in newton) required to maintain equilibrium of the ladder is

Two plane mirrors are inclined at angle θ as shown in figure. If a ray parallel to OB strikes the other mirror at P and finally emerges parallel to OA after two reflections, then θ is equal to

Two moles of an ideal monoatomic gas at 27∘C occupies a volume of V. If the gas is expanded adiabatically to the volume 23/2V, then the work done by the gas will be (γ=53,R=8.31 J/mol K)

Uranium ores contain one radium −226 atoms for every 2.8×106 uranium −238 atoms. Calculate the half - life of 23892U, given that the half - life of 22688Ra is 1600 years. (22688Ra is a decay product of 23892U)

Find at what depth of a pond the total pressure will be 1.5 times of the atmospheric pressure.

The ratio of electric potential on a equatorial and a axial point of short dipole will be 1 0

The wavelength of the matter wave is independent of

Will the average and instantaneous acceleration of the body vary of the object changes its direction of velocity or has a turning point .

The velocity of a particle is v=v0+gt+ft2. If its position is x=0 at t=0, then its displacement after unit time (t=1) is

A vector of length l is turned through the angle θ about its tail. What is the change in the position vector of its head?why should we take 180 -theta and why not 60 degree?when should we use phi value instead of theta?

A stationary person observes that rain is falling vertically down at 18 km/hr. A cyclist is moving in positive x- direction on the level road, at 24 km/hr. At what angle from the horizontal should the cyclist hold his umbrella to protect himself from rain?

Power Dilivered to an object of mass M is P. Velocity of object at time T is V .If it will start from rest then Calaulate power dilivered ty engine in time 't'

Potential energy U(x) and associated force F(x) bear the relation F(x)=−dU(x)dx. Dependence of potential energy of a two-particle system on the separation x between them is shown in the following figure. Which of the following graphs shows the correct variation of force F(x) with x?

The magnetic flux linked with a coil is given by the equation ϕ=2t2−8t+16. what will be the magnitude of flux linked with the coil, when induced emf in the coil is zero?

Burst the bubbles whose derivative is a straight line.

What were the observations that made us look for the existence of neutrons?

The charge per unit length of the four quadrant of the ring is 2λ, −2λ, λ and −λ respectively. Find the electric field at the centre.

A solid cylinder of mass m and radius r starts rolling down on inclined plane of inclination θ. Friction is sufficient enough to prevent slipping. Find the speed of centre of mass of solid cylinder, when it's centre of mass has fallen through a height of h=9 m. (Take g=10 m/s2)

What is the value of linear velocity, if →ω=3^i−4^j+^k and →r=5^i−6^j+6^k

A conducting rod of length l is hinged at point O. It is free to rotate in a vertical plane. The rod is released from the position shown. The potential difference between the two ends of the rod is proportional to

What physical quantity is the same for X-rays of wavelength10–10 m, red light of wavelength 6800 Å and radiowaves of wavelength 500m?

Two parallel plane sheets 1 and 2 carry uniform charge densities σ1 and σ2 (see Fig. 20.8). The electric field in the region marked I is (σ1>σ2). (Consider the right direction as the positive direction)