50278 + Interview Questions in Physics

1.	The phase difference between current and voltage in an AC circuit is /4 radian. Of the frequency of AC is 50Hz then the phase difference is equivalent to the Time difference of 1) 0.75s 2) 10.5ms 3) 2.5ms
Answer» The phase difference between current and voltage in an AC circuit is /4 radian. Of the frequency of AC is 50Hz then the phase difference is equivalent to the Time difference of 1) 0.75s 2) 10.5ms 3) 2.5ms

Discussion

2.	A particle is projected from a horizontal plane (x−z plane) such that its velocity vector at time t is given by →V=a^i+(b−ct)^j. Its range on the horizontal plane is given by
Answer» A particle is projected from a horizontal plane ( $x - z$ plane) such that its velocity vector at time $t$ is given by $\to V = a^i + (b - c t)^j$ . Its range on the horizontal plane is given by

Discussion

3.	If the temperature of a wire of length 2 m and area of cross-section 1 cm2 is increased from 0∘C to 80∘C, then force required so that the wire is not allowed to increase in length is: (Given Y=1010 N/m2,α=10−6 /∘C)
Answer» If the temperature of a wire of length $2 m$ and area of cross-section $1 {cm}^{2}$ is increased from $0^{\circ} C$ to $80^{\circ} C$ , then force required so that the wire is not allowed to increase in length is: (Given $Y = 10^{10} {N/m}^{2}, α = 10^{- 6} /^{\circ} C$ )

Discussion

4.	A particle of mass m is thrown upwards from the surface of the earth, with a velocity u. The mass and the radius of the earth are, respectively, M and R. G is gravitational constant and g is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to the earth is
Answer» A particle of mass $m$ is thrown upwards from the surface of the earth, with a velocity $u$ . The mass and the radius of the earth are, respectively, $M$ and $R$ . $G$ is gravitational constant and $g$ is acceleration due to gravity on the surface of the earth. The minimum value of $u$ so that the particle does not return back to the earth is

Discussion

5.	A 440 V, 50 Hz, 4 pole, 3-phase star-connected alternator has a rated full load current of 50 A. Its resistance per phase can be neglected. To induce rated voltage on no-load, a field current of 2 A is needed. When short circuited, the field excitation needed to circulate rated current in the phase is 1.5 A. When the machine is delivering rated load and rated voltage and a leading phase angle of 30o, the field current is ____ A.1.8
Answer» A 440 V, 50 Hz, 4 pole, 3-phase star-connected alternator has a rated full load current of 50 A. Its resistance per phase can be neglected. To induce rated voltage on no-load, a field current of 2 A is needed. When short circuited, the field excitation needed to circulate rated current in the phase is 1.5 A. When the machine is delivering rated load and rated voltage and a leading phase angle of $30^{o}$ , the field current is ____ A. 1.8

Discussion

6.	A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing, it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of
Answer» A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing, it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of

Discussion

7.	In the interference of two waves with identical amplitudes A0 and the intensity I0, the resultant intensity at a point where the path difference between two waves is λ3 will be
Answer» In the interference of two waves with identical amplitudes $A_{0}$ and the intensity $I_{0}$ , the resultant intensity at a point where the path difference between two waves is $\frac{λ}{3}$ will be

Discussion

8.	Two blocks of mass 2.9 kg and 1.9 kg are suspended from a rigid support S by two inextensible wires each of length 1 meter, as shown in the figure. The upper wire has negligible mass and the lower wire has a uniform mass of 0.2 kg/m. The whole system of blocks, wires and support have an upward acceleration of 0.2 m/s2. Acceleration due to gravity is 9.8 m/s2. Then the difference in tension at the mid point's (in N) of the upper wire and the lower wire is
Answer» Two blocks of mass 2.9 kg and 1.9 kg are suspended from a rigid support S by two inextensible wires each of length 1 meter, as shown in the figure. The upper wire has negligible mass and the lower wire has a uniform mass of 0.2 kg/m. The whole system of blocks, wires and support have an upward acceleration of 0.2 $m / s^{2}$ . Acceleration due to gravity is 9.8 $m / s^{2}$ . Then the difference in tension at the mid point's (in N) of the upper wire and the lower wire is

Discussion

9.	Why heat is a path function? How can we verify if a quantity is a path function?
Answer» Why heat is a path function? How can we verify if a quantity is a path function?

Discussion

10.	If S=exsinx, find d2Sdx2
Answer» If $S = e^{x} sin x$ , find $\frac{d^{2} S}{d x^{2}}$

Discussion

11.	Calculate the amplification factor of a triode valve which has plate resistance of 2kΩ and transconductance of 2 millimho.
Answer» Calculate the amplification factor of a triode valve which has plate resistance of $2 k Ω$ and transconductance of 2 millimho.

Discussion

12.	Velocity of two particle A and B at t=0 are Va=-10i Vb=-15j and initial position of A(10,0)m and B(0,20)m time when seperation between them will be minimum
Answer» Velocity of two particle A and B at t=0 are Va=-10i Vb=-15j and initial position of A(10,0)m and B(0,20)m time when seperation between them will be minimum

Discussion

13.	The equivalent resistance between points A and B is:
Answer» The equivalent resistance between points $A$ and $B$ is:

Discussion

14.	A quarter ring of radius is having uniform charge density.Find the electric field and potential at the centre of ring.
Answer» A quarter ring of radius is having uniform charge density.Find the electric field and potential at the centre of ring.

Discussion

15.

The different arrangements of incident beam and position of glass slab in a YDSE experiment have been shown in the figure. (a) (p) The zero order maxima will lie above point O.(b) (q) The zero order maxima will lie below point O.(c) (r) The zero order maxim a may lie above or below point O.(d) (s) The zero order maxima may lie at point O.Select the correct option.

Answer»

The different arrangements of incident beam and position of glass slab in a $YDSE$ experiment have been shown in the figure.

$(a)$	$(p)$ The zero order maxima will lie above point $O$ .
$(b)$	$(q)$ The zero order maxima will lie below point $O .$
$(c)$	$(r)$ The zero order maxim a may lie above or below point $O$ .
$(d)$	$(s)$ The zero order maxima may lie at point $O$ .

Select the correct option.

Discussion

16.	A force F acting on a particle varies with position x as shown in figure. The work done by this force in displacing the particle from x=−1 m to 1 m.
Answer» A force $F$ acting on a particle varies with position $x$ as shown in figure. The work done by this force in displacing the particle from $x = - 1 m$ to $1 m$ .

Discussion

17.	44.The distance through which a body falls in the nth second is "h" The distance through which it travels falls in the next second is "y" The distance through which it falls inn the next second is
Answer» 44.The distance through which a body falls in the nth second is "h" The distance through which it travels falls in the next second is "y" The distance through which it falls inn the next second is

Discussion

18.	if the dis†an ce between earth and sun is increased by 2% then find the change in gravitation force between them?
Answer» if the dis†an ce between earth and sun is increased by 2% then find the change in gravitation force between them?

Discussion

19.	A string of length L is taut between two cliffs. It is clamped at length L8. If a standing wave is formed on this string, what will be the maximum wavelength of the wave?
Answer» A string of length $L$ is taut between two cliffs. It is clamped at length $\frac{L}{8}$ . If a standing wave is formed on this string, what will be the maximum wavelength of the wave?

Discussion

20.	Which of the following is a correct truth table for the circuit shown in figure?
Answer» Which of the following is a correct truth table for the circuit shown in figure?

Discussion

21.	Electric field atcentre of uniformly charged ring is zero what is the electric field at center of half if charge on it be Q and radius be R
Answer» Electric field atcentre of uniformly charged ring is zero what is the electric field at center of half if charge on it be Q and radius be R

Discussion

22.	A circular disc with a groove along its diameter is placed horizontally. A ball of mass 1 kg is placed in it as shown. The co-efficient of friction between the ball and all surfaces of the groove in contact is μ=25. The disc has an acceleration of 25 m/s2. Then, the acceleration of the ball with respect to disc will be[Take θ=37∘ and g=10 m/s2]
Answer» A circular disc with a groove along its diameter is placed horizontally. A ball of mass $1 kg$ is placed in it as shown. The co-efficient of friction between the ball and all surfaces of the groove in contact is $μ = \frac{2}{5}$ . The disc has an acceleration of $25 {m/s}^{2}$ . Then, the acceleration of the ball with respect to disc will be [Take $θ = 37^{\circ}$ and $g = 10 {m/s}^{2}$ ]

Discussion

23.	A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge -Q. The surface charge density on the inner and outer surfaces of the spherical shell will be?
Answer» A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge -Q. The surface charge density on the inner and outer surfaces of the spherical shell will be?

Discussion

24.	Two metal rods of same length and same area of cross section are fixed, end to end between rigid supports. Young's modulus of elasticity of two metal rods are Y1 and Y2, and coefficient of linear expansion are αl and α2. When the rods are cooled the junction does not change its position, if
Answer» Two metal rods of same length and same area of cross section are fixed, end to end between rigid supports. Young's modulus of elasticity of two metal rods are $Y_{1} a n d Y_{2}$ , and coefficient of linear expansion are $α_{l} a n d α_{2}$ . When the rods are cooled the junction does not change its position, if

Discussion

25.	A frictionless track ABCDE ends in a circular ends in a circular loop of radius R . A body slides down the track from point A which is at a height 5cm . Maximum value of R for the body to successfully complete the loop is
Answer» A frictionless track ABCDE ends in a circular ends in a circular loop of radius R . A body slides down the track from point A which is at a height 5cm . Maximum value of R for the body to successfully complete the loop is

Discussion

26.	A loop carrying current I lies in the x−y plane as shown in the figure. The unit vector ^k is coming out of the plane of the paper. The magnetic moment of the current loop isDiagram
Answer» A loop carrying current I lies in the $x - y$ plane as shown in the figure. The unit vector $^k$ is coming out of the plane of the paper. The magnetic moment of the current loop is Diagram

Discussion

27.	Two rods of same length but made of different material are taken for a study as shown in the figure. Area of cross-section of rod 1 is 12 cm2 and that of rod 2 is 16 cm2. Thermal conductivity of rod 1 is 0.0008 cal/cm-s-∘C. If rate of loss of heat due to conduction is equal, find the thermal conductivity of rod 2.
Answer» Two rods of same length but made of different material are taken for a study as shown in the figure. Area of cross-section of rod $1$ is $12 {cm}^{2}$ and that of rod $2$ is $16 {cm}^{2}$ . Thermal conductivity of rod $1$ is $0.0008 {cal/cm-s-}^{\circ} C$ . If rate of loss of heat due to conduction is equal, find the thermal conductivity of rod $2$ .

Discussion

28.	A small block slides down from the top of a inverted hemisphere of radius r. It is assumed that there is no friction between the block and the hemisphere. At what height h from ground, will the block lose contact with the surface of sphere ?
Answer» A small block slides down from the top of a inverted hemisphere of radius $r$ . It is assumed that there is no friction between the block and the hemisphere. At what height $h$ from ground, will the block lose contact with the surface of sphere ?

Discussion

29.	A piece of copper having a rectangular cross-section of 15.2 mm × 19.1 mm is pulled in tension with 44,500 N force, producing only elastic deformation. Calculate the resulting strain? (Take modulus of elasticity of copper 140×109 m/sec2)
Answer» A piece of copper having a rectangular cross-section of 15.2 mm × 19.1 mm is pulled in tension with 44,500 N force, producing only elastic deformation. Calculate the resulting strain? (Take modulus of elasticity of copper $140 \times 10^{9} m / s e c^{2}$ )

Discussion

30.	A swimmer jumps from a bridge over a canal and swims 1 km up stream. After that first km, he passes a floating cork. He continues swimming for half an hour and then turns around and swims back to the bridge. The swimmer and the cork reach the bridge at the same time. The swimmer has been swimming at a constant speed. How fast does the water in the canal flow in km/hr?
Answer» A swimmer jumps from a bridge over a canal and swims $1 km$ up stream. After that first $km$ , he passes a floating cork. He continues swimming for half an hour and then turns around and swims back to the bridge. The swimmer and the cork reach the bridge at the same time. The swimmer has been swimming at a constant speed. How fast does the water in the canal flow in $km/hr$ ?

Discussion

31.	A piano wire B vibrates at a fundamental frequency of 600 Hz. A second identical wire A produces 6 beats per second with it when the tension in A is slightly increased. Find the ratio of the tension in A to the tension in B.
Answer» A piano wire B vibrates at a fundamental frequency of 600 Hz. A second identical wire A produces 6 beats per second with it when the tension in A is slightly increased. Find the ratio of the tension in A to the tension in B.

Discussion

32.	A ray parallel to principle axis at height R/2 hits concave mirror and cut principle axis at point O. Length PO is
Answer» A ray parallel to principle axis at height R/2 hits concave mirror and cut principle axis at point O. Length PO is

Discussion

33.	One second after projection, a stone moves at an angle 45∘ with horizontal. Two seconds after projection, it moves horizontally. It's angle of projection is- [g=10 ms2]
Answer» One second after projection, a stone moves at an angle $45^{\circ}$ with horizontal. Two seconds after projection, it moves horizontally. It's angle of projection is- $[g = 10 \frac{m}{s^{2}}]$

Discussion

34.	A metallic sphere cools from 50 ∘C to 40 ∘C in 300 s. If atmospheric temperature around is 20 ∘C, then the sphere's temperature after the next 5 minutes will be close to:
Answer» A metallic sphere cools from $50^{\circ} C$ to $40^{\circ} C$ in $300 s$ . If atmospheric temperature around is $20^{\circ} C$ , then the sphere's temperature after the next $5 minutes$ will be close to:

Discussion

35.	25. What would be the electrostatic force between two aluminium spheres each of mass 1g separated by a distance of 1m, if the total electronic charge on the sphere differed from the total positive charge of the nuclei on any one of the sphere by one percent?
Answer» 25. What would be the electrostatic force between two aluminium spheres each of mass 1g separated by a distance of 1m, if the total electronic charge on the sphere differed from the total positive charge of the nuclei on any one of the sphere by one percent?

Discussion

36.	A solid cylinder of radius R carries a current such that the current density varies as j=j0(1−rR). Find the B - field at r=R2 from the axis.
Answer» A solid cylinder of radius R carries a current such that the current density varies as $j = j_{0} (1 - \frac{r}{R})$ . Find the B - field at $r = \frac{R}{2}$ from the axis.

Discussion

37.	12 Number of unpaired electrons in [Cr(en)3]2+
Answer» 12 Number of unpaired electrons in [Cr(en)3]2+

Discussion

38.	A generator produces time varying voltage given by E=240sin120t, where t is in second. The average value of voltage for the half cycle is -
Answer» A generator produces time varying voltage given by $E = 240 sin 120 t$ , where $t$ is in second. The average value of voltage for the half cycle is -

Discussion

39.	In a compound microscope, the focal length of the objective lens is 1.2 cm and the focal length of the eyepiece is 3 cm. When the object is kept at 1.25 cm in front of the objective lens, the final image is formed at infinity. The magnifying power of the compound microscope is -
Answer» In a compound microscope, the focal length of the objective lens is $1.2 cm$ and the focal length of the eyepiece is $3 cm$ . When the object is kept at $1.25 cm$ in front of the objective lens, the final image is formed at infinity. The magnifying power of the compound microscope is -

Discussion

40.	Two point charges q and 2q are placed some dis†an ce apart. if the electric field at the location of q be E then that qt the location of 2q will be 1. 3E 2. E/2 3. E 4. none of thes
Answer» Two point charges q and 2q are placed some dis†an ce apart. if the electric field at the location of q be E then that qt the location of 2q will be 1. 3E 2. E/2 3. E 4. none of thes

Discussion

41.	The upper half of an inclined plane of inclination is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by θ.
Answer» The upper half of an inclined plane of inclination is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by $θ$ .

Discussion

42.	Which of the following graph represents the variation of resistivity (ρ) with temperature (T) for nichrome?
Answer» Which of the following graph represents the variation of resistivity $(ρ)$ with temperature $(T)$ for nichrome?

Discussion

43.	The speed of projectile at maximum height is half of initial speed
Answer» The speed of projectile at maximum height is half of initial speed

Discussion

44.	An athlete completes one round of a circular track of radius R in 30 sec. What will be the magnitude of displacement at the end of 2 min 30 sec?
Answer» An athlete completes one round of a circular track of radius $R$ in $30$ sec. What will be the magnitude of displacement at the end of $2$ min $30$ sec?

Discussion

45.	A lens with a focal length of f=30 cm produces on a screen a sharp image of an object that is at a distance of a=40 cm from the lens. A plane parallel plate with thickness of d=9 cm is placed between the lens and the object perpendicular to the optical axis of the lens. Through what distance (in cm) should the screen be shifted for the image of the object to remain distinct? The refractive index of the glass of the plate is μ=1.8
Answer» A lens with a focal length of $f = 30 cm$ produces on a screen a sharp image of an object that is at a distance of $a = 40 cm$ from the lens. A plane parallel plate with thickness of $d = 9 cm$ is placed between the lens and the object perpendicular to the optical axis of the lens. Through what distance (in $cm)$ should the screen be shifted for the image of the object to remain distinct? The refractive index of the glass of the plate is $μ = 1.8$

Discussion

46.	A man of mass 50 kg is in a lift at ground floor. The man is now on a weight machine. For first 10 s, reading of weighing machine is 60 kg-wt. For next 10 s, it reads 50 kg-wt and for rest of the journey till top floor, reading of weighing machine is 30 kg-wt. Assume that initial and final velocity of lift is zero. Total distance travelled by the lift is 50x m. The value of x is _______.(g=10 m/s2)
Answer» A man of mass $50 kg$ is in a lift at ground floor. The man is now on a weight machine. For first $10 s$ , reading of weighing machine is $60 kg-wt$ . For next $10 s$ , it reads $50 kg-wt$ and for rest of the journey till top floor, reading of weighing machine is $30 kg-wt$ . Assume that initial and final velocity of lift is zero. Total distance travelled by the lift is $50 x m$ . The value of $x$ is _______. $(g = 10 {m/s}^{2})$

Discussion

47.	A rectangular block of mass m and area of cross section A in a liquid of density d . If it is given small vertical displacement from equilibrium it undergoes oscillation with time period T. Then
Answer» A rectangular block of mass m and area of cross section A in a liquid of density d . If it is given small vertical displacement from equilibrium it undergoes oscillation with time period T. Then

Discussion

48.	An electron is projected as shown in the figure, with kinetic energy K, at an angle θ=45∘ between two charged plates. Ignore the gravity. At what distance from the starting point will the electron strike the lower plate?
Answer» An electron is projected as shown in the figure, with kinetic energy K, at an angle $θ = 45^{\circ}$ between two charged plates. Ignore the gravity. At what distance from the starting point will the electron strike the lower plate?

Discussion

49.	A light ray is incident perpendicular to a face of a 90∘ prism and is totally internally reflected at the glass – air interface. If the angle of reflection is 45∘, what can be concluded about the refractive index n?
Answer» A light ray is incident perpendicular to a face of a $90^{\circ}$ prism and is totally internally reflected at the glass – air interface. If the angle of reflection is $45^{\circ}$ , what can be concluded about the refractive index n?

Discussion

50.	A taxi leaves the station X for statiin Y every 10 minutes .simultaneously a taxi leaves the station Y also for station X every 10 minutes .The taxis move at same constant speed and go from Y to X or vice versa in 2 hrs .How many taxis coming from other side will each taxi meet enroute from Y to X ?
Answer» A taxi leaves the station X for statiin Y every 10 minutes .simultaneously a taxi leaves the station Y also for station X every 10 minutes .The taxis move at same constant speed and go from Y to X or vice versa in 2 hrs .How many taxis coming from other side will each taxi meet enroute from Y to X ?

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

The phase difference between current and voltage in an AC circuit is /4 radian. Of the frequency of AC is 50Hz then the phase difference is equivalent to the Time difference of 1) 0.75s 2) 10.5ms 3) 2.5ms

A particle is projected from a horizontal plane (x−z plane) such that its velocity vector at time t is given by →V=a^i+(b−ct)^j. Its range on the horizontal plane is given by

If the temperature of a wire of length 2 m and area of cross-section 1 cm2 is increased from 0∘C to 80∘C, then force required so that the wire is not allowed to increase in length is: (Given Y=1010 N/m2,α=10−6 /∘C)

A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing, it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of

In the interference of two waves with identical amplitudes A0 and the intensity I0, the resultant intensity at a point where the path difference between two waves is λ3 will be

Why heat is a path function? How can we verify if a quantity is a path function?

If S=exsinx, find d2Sdx2

Calculate the amplification factor of a triode valve which has plate resistance of 2kΩ and transconductance of 2 millimho.

Velocity of two particle A and B at t=0 are Va=-10i Vb=-15j and initial position of A(10,0)m and B(0,20)m time when seperation between them will be minimum

The equivalent resistance between points A and B is:

A quarter ring of radius is having uniform charge density.Find the electric field and potential at the centre of ring.

A force F acting on a particle varies with position x as shown in figure. The work done by this force in displacing the particle from x=−1 m to 1 m.

44.The distance through which a body falls in the nth second is "h" The distance through which it travels falls in the next second is "y" The distance through which it falls inn the next second is

if the dis†an ce between earth and sun is increased by 2% then find the change in gravitation force between them?

A string of length L is taut between two cliffs. It is clamped at length L8. If a standing wave is formed on this string, what will be the maximum wavelength of the wave?

Which of the following is a correct truth table for the circuit shown in figure?

Electric field atcentre of uniformly charged ring is zero what is the electric field at center of half if charge on it be Q and radius be R

A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge -Q. The surface charge density on the inner and outer surfaces of the spherical shell will be?

Two metal rods of same length and same area of cross section are fixed, end to end between rigid supports. Young's modulus of elasticity of two metal rods are Y1 and Y2, and coefficient of linear expansion are αl and α2. When the rods are cooled the junction does not change its position, if

A frictionless track ABCDE ends in a circular ends in a circular loop of radius R . A body slides down the track from point A which is at a height 5cm . Maximum value of R for the body to successfully complete the loop is

A loop carrying current I lies in the x−y plane as shown in the figure. The unit vector ^k is coming out of the plane of the paper. The magnetic moment of the current loop isDiagram

A small block slides down from the top of a inverted hemisphere of radius r. It is assumed that there is no friction between the block and the hemisphere. At what height h from ground, will the block lose contact with the surface of sphere ?

A piece of copper having a rectangular cross-section of 15.2 mm × 19.1 mm is pulled in tension with 44,500 N force, producing only elastic deformation. Calculate the resulting strain? (Take modulus of elasticity of copper 140×109 m/sec2)

A piano wire B vibrates at a fundamental frequency of 600 Hz. A second identical wire A produces 6 beats per second with it when the tension in A is slightly increased. Find the ratio of the tension in A to the tension in B.

A ray parallel to principle axis at height R/2 hits concave mirror and cut principle axis at point O. Length PO is

One second after projection, a stone moves at an angle 45∘ with horizontal. Two seconds after projection, it moves horizontally. It's angle of projection is- [g=10 ms2]

A metallic sphere cools from 50 ∘C to 40 ∘C in 300 s. If atmospheric temperature around is 20 ∘C, then the sphere's temperature after the next 5 minutes will be close to:

25. What would be the electrostatic force between two aluminium spheres each of mass 1g separated by a distance of 1m, if the total electronic charge on the sphere differed from the total positive charge of the nuclei on any one of the sphere by one percent?

A solid cylinder of radius R carries a current such that the current density varies as j=j0(1−rR). Find the B - field at r=R2 from the axis.

12 Number of unpaired electrons in [Cr(en)3]2+

A generator produces time varying voltage given by E=240sin120t, where t is in second. The average value of voltage for the half cycle is -

In a compound microscope, the focal length of the objective lens is 1.2 cm and the focal length of the eyepiece is 3 cm. When the object is kept at 1.25 cm in front of the objective lens, the final image is formed at infinity. The magnifying power of the compound microscope is -

Two point charges q and 2q are placed some dis†an ce apart. if the electric field at the location of q be E then that qt the location of 2q will be 1. 3E 2. E/2 3. E 4. none of thes

The upper half of an inclined plane of inclination is perfectly smooth while lower half is rough. A block starting from rest at the top of the plane will again come to rest at the bottom, if the coefficient of friction between the block and lower half of the plane is given by θ.

Which of the following graph represents the variation of resistivity (ρ) with temperature (T) for nichrome?

The speed of projectile at maximum height is half of initial speed

An athlete completes one round of a circular track of radius R in 30 sec. What will be the magnitude of displacement at the end of 2 min 30 sec?

A rectangular block of mass m and area of cross section A in a liquid of density d . If it is given small vertical displacement from equilibrium it undergoes oscillation with time period T. Then

An electron is projected as shown in the figure, with kinetic energy K, at an angle θ=45∘ between two charged plates. Ignore the gravity. At what distance from the starting point will the electron strike the lower plate?

A light ray is incident perpendicular to a face of a 90∘ prism and is totally internally reflected at the glass – air interface. If the angle of reflection is 45∘, what can be concluded about the refractive index n?