50278 + Interview Questions in Physics

1.	In the given figure, net magnetic field at O will be
Answer» In the given figure, net magnetic field at $O$ will be

Discussion

2.	How dF/dq=0 for maximum electrostatic repulxion
Answer» How dF/dq=0 for maximum electrostatic repulxion

Discussion

3.	If a stone tied to the end of a string 80cm long is whirled in a horizontal circle with a speed. If the stone makes 14 revolutions in 25sec., then the magnitude and direction of acceleration of the stone is?
Answer» If a stone tied to the end of a string 80cm long is whirled in a horizontal circle with a speed. If the stone makes 14 revolutions in 25sec., then the magnitude and direction of acceleration of the stone is?

Discussion

4.	In a resistance thermometer the resistances at 0∘C and 100∘C and 6.74 and 7.74 ohm respectively. The temperature corresponding to 6.53 ohm resistance is
Answer» In a resistance thermometer the resistances at $0^{\circ} C$ and $100^{\circ} C$ and 6.74 and 7.74 ohm respectively. The temperature corresponding to 6.53 ohm resistance is

Discussion

5.	A magnet is suspended in the magnetic meridian with an untwisted wire. The upper end of wire is rotated through 181^° to deflect magnet by 37^° from magnetic meridian. Now this magnet is replaced by another magnet and upper end of wire has to be rotated by 273^° to deflect magnet by 53^° from magnetic meridian. The ratio of magnetic moment of the two magnets respectively is
Answer» A magnet is suspended in the magnetic meridian with an untwisted wire. The upper end of wire is rotated through 181^° to deflect magnet by 37^° from magnetic meridian. Now this magnet is replaced by another magnet and upper end of wire has to be rotated by 273^° to deflect magnet by 53^° from magnetic meridian. The ratio of magnetic moment of the two magnets respectively is

Discussion

6.	An open container as shown in figure is filled with water (ρ=103 kg/m3) upto height 8 m. If it starts moving with acceleration 9.81 m/s2, determine the pressure difference between points A and B.[Take g=9.81 m/s2]
Answer» An open container as shown in figure is filled with water $(ρ = 10^{3} {kg/m}^{3})$ upto height $8 m$ . If it starts moving with acceleration $9.81 {m/s}^{2}$ , determine the pressure difference between points $A$ and $B$ . [Take $g = 9.81 {m/s}^{2}$ ]

Discussion

7.	For a microscopic object it's kinetic energy has become 4 time then how many has its wave length changed?
Answer» For a microscopic object it's kinetic energy has become 4 time then how many has its wave length changed?

Discussion

8.	Water and mercury are filled in two cylindrical vessels upto same height. Both vessels have a hole in the wall near the bottom. The velocity of water and mercury coming out of the holes are v1 and v2 respectively. Thus
Answer» Water and mercury are filled in two cylindrical vessels upto same height. Both vessels have a hole in the wall near the bottom. The velocity of water and mercury coming out of the holes are $v_{1}$ and $v_{2}$ respectively. Thus

Discussion

9.	If momentum of an object is increased by 10% then its kinetic energy will increase by
Answer» If momentum of an object is increased by 10% then its kinetic energy will increase by

Discussion

10.	20.A projectile is fired vertically upwards from the surface of the earth with a velocity I've,where be is the escape velocity and k
Answer» 20.A projectile is fired vertically upwards from the surface of the earth with a velocity I've,where be is the escape velocity and k<1.If R is the radius of the earth, the maximum height to which it will rise , measured from the center of the earth,wii be (Neglect air resistance)

Discussion

11.	Currents flowing in a solenoid and a toroid are 2i and 6i respectively. If the number of turns per unit length is 2n and n respectively. Find the ratio of magnetic field inside the core due to solenoid and toroid.
Answer» Currents flowing in a solenoid and a toroid are $2 i$ and $6 i$ respectively. If the number of turns per unit length is $2 n$ and $n$ respectively. Find the ratio of magnetic field inside the core due to solenoid and toroid.

Discussion

12.	An object is projected upwards with a velocity of 100 m/s.The time after which it will strike the ground is (g = 10ms−2)
Answer» An object is projected upwards with a velocity of 100 m/s.The time after which it will strike the ground is (g = $10 m s^{- 2})$

Discussion

13.	69. A cell of Emf E and internal resistance r drives a current I through an external resistance R. Select the incorrect option 1) the cell supplies a power EI 2) the heat is produced in R at the rate EI 3) the heat is produced in R at the rate EI R upon R+r 4)the heat is produced in cell at the rate EIr upon R+
Answer» 69. A cell of Emf E and internal resistance r drives a current I through an external resistance R. Select the incorrect option 1) the cell supplies a power EI 2) the heat is produced in R at the rate EI 3) the heat is produced in R at the rate EI R upon R+r 4)the heat is produced in cell at the rate EIr upon R+

Discussion

14.	Three uncharged capacitors of capacitance C1=1 μF, C2=2 μF and C3=3 μF are connected as shown in figure. If potential at shown points are VA=10 V; VB=25 V and VD=20 V. The potential at point O will be
Answer» Three uncharged capacitors of capacitance $C_{1} = 1 μ F, C_{2} = 2 μ F$ and $C_{3} = 3 μ F$ are connected as shown in figure. If potential at shown points are $V_{A} = 10 V; V_{B} = 25 V$ and $V_{D} = 20 V$ . The potential at point $O$ will be

Discussion

15.	18. what is equivalent weight??
Answer» 18. what is equivalent weight??

Discussion

16.	A cylinder fixed with a piston contains saturated vapour of a refrigerant at 10∘C, the volume and pressure are 10 L and 0.681 MPa respectively. The refrigerant is compressed to 3.5 L and 2 MPa. If the saturated vapour is undergoing polytropic process as PVn= constant, where n=1.025, then calculate the work done during the process.
Answer» A cylinder fixed with a piston contains saturated vapour of a refrigerant at $10^{\circ} C,$ the volume and pressure are $10 L$ and $0.681 MPa$ respectively. The refrigerant is compressed to $3.5 L$ and $2 MPa$ . If the saturated vapour is undergoing polytropic process as $P V^{n} =$ constant, where $n = 1.025,$ then calculate the work done during the process.

Discussion

17.	For a particular MOSFET operating in the saturation region at a constant gate to source voltage (VGS), drain current (ID) is found to be 2 mA VDS=4V and 2.5 mA for VDS=8V.Then the value of λ 'is_____V−1(Whereλ is channel length modulation parameter).0.083
Answer» For a particular MOSFET operating in the saturation region at a constant gate to source voltage $(V_{G S}),$ drain current $(I_{D})$ is found to be 2 mA $V_{D S} = 4 V a n d 2.5 m A f o r V_{D S} = 8 V .$ Then the value of $λ$ 'is_____ $V^{- 1}$ (Where $λ$ is channel length modulation parameter). 0.083

Discussion

18.	A transformer is used to light 100 W – 110 V lamp from 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is
Answer» A transformer is used to light 100 W – 110 V lamp from 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is

Discussion

19.	An open U tube contain Mercury . When 13.6cm of water is poured into one of the arm of tube then Mercury rise in other arm from its initial level is
Answer» An open U tube contain Mercury . When 13.6cm of water is poured into one of the arm of tube then Mercury rise in other arm from its initial level is

Discussion

20.	How do gases exert pressure?
Answer» How do gases exert pressure?

Discussion

21.	A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad s-1. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder? What is the magnitude of angular momentum of the cylinder about its axis?
Answer» A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad s-1. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder? What is the magnitude of angular momentum of the cylinder about its axis?

Discussion

22.	A simple pendulum having a bob of mass m is suspended from the ceiling of a car used in a stunt film shooting. The car moves up along an inclined cliff at a speed v and makes a jump to leave the cliff and lands at some distance. Let R be the maximum height of the car from the top of the cliff. The tension in the string when the car is in air is
Answer» A simple pendulum having a bob of mass m is suspended from the ceiling of a car used in a stunt film shooting. The car moves up along an inclined cliff at a speed v and makes a jump to leave the cliff and lands at some distance. Let R be the maximum height of the car from the top of the cliff. The tension in the string when the car is in air is

Discussion

23.	Why is angle between m and B in moving coil galvanometer =90°?
Answer» Why is angle between m and B in moving coil galvanometer =90°?

Discussion

24.	For a given length of the wire, carrying a current I, how many circular turns will produce maximum magnetic moment ?
Answer» For a given length of the wire, carrying a current $I$ , how many circular turns will produce maximum magnetic moment ?

Discussion

25.	151 A source of emf E =10 V and having negligible internal resistance is connected to a variable resistance. The resistance varies as shown in figure. The total charge that has passed through the resistor R during the time interval from t1 to t2, is (a) 40 loge 4 (b) 30 loge 3 (c) 20 loge 2 (d) 10 loge 2
Answer» 151 A source of emf E =10 V and having negligible internal resistance is connected to a variable resistance. The resistance varies as shown in figure. The total charge that has passed through the resistor R during the time interval from t1 to t2, is (a) 40 loge 4 (b) 30 loge 3 (c) 20 loge 2 (d) 10 loge 2

Discussion

26.	A galvanometer has a resistance of 50 Ω and its full-scale deflection current is 50 μA. What shunt resistance should be added so that the ammeter can have a range of 0−5 mA ?
Answer» A galvanometer has a resistance of $50 Ω$ and its full-scale deflection current is $50 μ A$ . What shunt resistance should be added so that the ammeter can have a range of $0 - 5 mA$ ?

Discussion

27.	The particle changes its position with respect to time as x = (2t^3 – 3t^2 + 2t +2) m, the velocity of particle when acceleration is zero isOptions:1.5 m0.5 m2.5 m1 m
Answer» The particle changes its position with respect to time as x = (2t^3 – 3t^2 + 2t +2) m, the velocity of particle when acceleration is zero is Options: 1.5 m 0.5 m 2.5 m 1 m

Discussion

28.	A uniform disc of mass m and radius R is projected horizontally with velocity v0 on a rough horizontal floor, so that it starts off with a purely sliding motion at t=0. After t0 seconds, it acquires a purely rolling motion as shown in figure.
Answer» A uniform disc of mass m and radius R is projected horizontally with velocity $v_{0}$ on a rough horizontal floor, so that it starts off with a purely sliding motion at t=0. After $t_{0}$ seconds, it acquires a purely rolling motion as shown in figure.

28.

A uniform disc of mass m and radius R is projected horizontally with velocity v0 on a rough horizontal floor, so that it starts off with a purely sliding motion at t=0. After t0 seconds, it acquires a purely rolling motion as shown in figure.

Answer»

A uniform disc of mass m and radius R is projected horizontally with velocity $v_{0}$ on a rough horizontal floor, so that it starts off with a purely sliding motion at t=0. After $t_{0}$ seconds, it acquires a purely rolling motion as shown in figure.

Discussion

29.	Suppose a vertical tunnel is along the diameter of earth, assumed to be a sphere of uniform mass density p. If a body of mass m is thrown in this tunnel, its acceleration at a distance y from the centre is given bya) (4pi/3)Gpymb) (3pi/4)Gpymc) (4pi/3)pyd) (4pi/3)Gpy
Answer» Suppose a vertical tunnel is along the diameter of earth, assumed to be a sphere of uniform mass density p. If a body of mass m is thrown in this tunnel, its acceleration at a distance y from the centre is given by a) (4pi/3)Gpym b) (3pi/4)Gpym c) (4pi/3)py d) (4pi/3)Gpy

Discussion

30.	WHY ELECTRIC LINES OF FORCES ARE PERPENDICULAR TO THE SURFACE OF CONDUCTOR?
Answer» WHY ELECTRIC LINES OF FORCES ARE PERPENDICULAR TO THE SURFACE OF CONDUCTOR?

Discussion

31.	If √1849+√0.06+x2=43.25, then x is
Answer» If $\sqrt{1849} + \sqrt{0.06 + x^{2}} = 43.25$ , then x is

Discussion

32.	Two balls of masses 2 kg and 5 kg moving on a frictionless surface, collide head-on with speeds 2 m/s and 3 m/s as shown in figure. If the coefficient of restitution is 0.25, then the kinetic energy lost by the balls is
Answer» Two balls of masses $2 kg$ and $5 kg$ moving on a frictionless surface, collide head-on with speeds $2 m/s$ and $3 m/s$ as shown in figure. If the coefficient of restitution is $0.25$ , then the kinetic energy lost by the balls is

Discussion

33.	In the given arrangement, the loop is moved with constant velocity V in a uniform magnetic field B in a restricted region of width a. The time for which the emf is induced in the circuit is
Answer» In the given arrangement, the loop is moved with constant velocity $V$ in a uniform magnetic field $B$ in a restricted region of width $a$ . The time for which the $emf$ is induced in the circuit is

Discussion

34.	in the reaction , H_2 + I_2 → 2HI , entropy increases or decreases ? explai
Answer» in the reaction , H_2 + I_2 → 2HI , entropy increases or decreases ? explai

Discussion

35.	A sphere having charge +q is surrounded by a uncharged shell. At this time their potential difference is &quotV". Now the uncharged shell is given a charge of -3q. The new potential difference will be ??
Answer» A sphere having charge +q is surrounded by a uncharged shell. At this time their potential difference is "V". Now the uncharged shell is given a charge of -3q. The new potential difference will be ??

Discussion

36.	A metal Rod of length r kept rotating with a constant angular speed Omega.A uniform and Constant Magnetic Field Is Applied Perpendicular and into the plane of Rotation.Then Find EMF induced.
Answer» A metal Rod of length r kept rotating with a constant angular speed Omega.A uniform and Constant Magnetic Field Is Applied Perpendicular and into the plane of Rotation.Then Find EMF induced.

Discussion

37.	the density of neon will be highest at 1)STP 2)0^0c and 2atm 3)273^0c and 1 atm 4)273^0c and 2 atm
Answer» the density of neon will be highest at 1)STP 2)0^0c and 2atm 3)273^0c and 1 atm 4)273^0c and 2 atm

Discussion

38.	An icebox made of 1.5 cm thick Styrofoam has dimensions 60 cm×60 cm×30 cm. It contains ice at 0∘C and is kept in a room at 40∘C. Find the rate at which the ice is melting. Latent heat of fusion of ice = 3.36×105J/kg. and thermal conductivity of Styrofoam = 0.04W/m∘C.
Answer» An icebox made of 1.5 cm thick Styrofoam has dimensions $60 c m \times 60 c m \times 30 c m$ . It contains ice at $0^{\circ} C$ and is kept in a room at $40^{\circ} C$ . Find the rate at which the ice is melting. Latent heat of fusion of ice = $3.36 \times 10^{5} J / k g$ . and thermal conductivity of Styrofoam = $0.04 W / m^{\circ} C$ .

Discussion

39.	Identify the gates P and Q shown in the figure. Write the truth table for the combination of the gates shown.Name the equivalent gate representing this circuit and write its logic symbol.
Answer» Identify the gates P and Q shown in the figure. Write the truth table for the combination of the gates shown. Name the equivalent gate representing this circuit and write its logic symbol.

Discussion

40.	A particle is moving in a circular path of radius 1 m.if its angular speed is 2pi rad/sec
Answer» A particle is moving in a circular path of radius 1 m.if its angular speed is 2pi rad/sec

Discussion

41.	Under isothermal condition, two soap bubbles of radii r1 and r2 coalesce to form a single bubble of radius r. The external pressure is P0. Find the surface tension of the soap in terms of the given parameters.
Answer» Under isothermal condition, two soap bubbles of radii $r_{1}$ and $r_{2}$ coalesce to form a single bubble of radius $r$ . The external pressure is $P_{0}$ . Find the surface tension of the soap in terms of the given parameters.

Discussion

42.	A body executing linear simple harmonic motion has a velocity of 3 cm/s, when its displacement is 4 cm and a velocity of 4 cm/s, when its displacement is 3 cm. What is the amplitude of oscillation?
Answer» A body executing linear simple harmonic motion has a velocity of $3 c m / s$ , when its displacement is $4 c m$ and a velocity of $4 c m / s$ , when its displacement is $3 c m$ . What is the amplitude of oscillation?

Discussion

43.	A ball is thrown into a lake from a tower 20 m above the water surface. The ball hits the water after 1 sec with a velocity v and then sinks to the bottom of the lake. It comes to rest at the bottom of the lake 6 sec after it was thrown. Find the acceleration of the ball inside the lake and the depth of the lake.
Answer» A ball is thrown into a lake from a tower $20 m$ above the water surface. The ball hits the water after $1 sec$ with a velocity $v$ and then sinks to the bottom of the lake. It comes to rest at the bottom of the lake $6 sec$ after it was thrown. Find the acceleration of the ball inside the lake and the depth of the lake.

Discussion

44.	nta rifle looses1/20thof its velocity in passing through a lank . the least no. of plank required to just stop the bulletn
Answer» nta rifle looses1/20thof its velocity in passing through a lank . the least no. of plank required to just stop the bulletn

Discussion

45.	Find the value of R, such that maximum power is transfereed to it.
Answer» Find the value of $R$ , such that maximum power is transfereed to it.

Discussion

46.	A solid sphere rolls down from the top of an inclined plane. Its linear velocity, on reaching the bottom of the plane, is v. When the same sphere slides down (without friction) from the top of the identical inclined plane, its linear velocity on reaching the bottom is v′. The ratio v′v is -
Answer» A solid sphere rolls down from the top of an inclined plane. Its linear velocity, on reaching the bottom of the plane, is $v$ . When the same sphere slides down (without friction) from the top of the identical inclined plane, its linear velocity on reaching the bottom is $v^{'}$ . The ratio $\frac{v^{'}}{v}$ is -

Discussion

47.	22. A screen is placed 90cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20cm. Determine the focal length of the lens
Answer» 22. A screen is placed 90cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20cm. Determine the focal length of the lens

Discussion

48.	Find the derivative of f(t)=4t−16t3+8t5.
Answer» Find the derivative of $f (t) = \frac{4}{t} - \frac{1}{6 t^{3}} + \frac{8}{t^{5}}$ .

Discussion

49.	Plane angle is obtained by dividing arc length by radius then it should be a derived quantity but why do we call it as fundamental quantity?
Answer» Plane angle is obtained by dividing arc length by radius then it should be a derived quantity but why do we call it as fundamental quantity?

Discussion

50.	Two small balls having equal positive charges Q (coulomb) on each are suspended by two insulating strings of equal length L (metre) from a hook fixed to a stand. The whole setup is taken in a satellite into space where there is no gravity (state of weightlessness). The angle between the two strings and the tension in each string is
Answer» Two small balls having equal positive charges $Q$ $(coulomb)$ on each are suspended by two insulating strings of equal length $L$ $(metre)$ from a hook fixed to a stand. The whole setup is taken in a satellite into space where there is no gravity $($ state of weightlessness $)$ . The angle between the two strings and the tension in each string is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

In the given figure, net magnetic field at O will be

How dF/dq=0 for maximum electrostatic repulxion

If a stone tied to the end of a string 80cm long is whirled in a horizontal circle with a speed. If the stone makes 14 revolutions in 25sec., then the magnitude and direction of acceleration of the stone is?

In a resistance thermometer the resistances at 0∘C and 100∘C and 6.74 and 7.74 ohm respectively. The temperature corresponding to 6.53 ohm resistance is

An open container as shown in figure is filled with water (ρ=103 kg/m3) upto height 8 m. If it starts moving with acceleration 9.81 m/s2, determine the pressure difference between points A and B.[Take g=9.81 m/s2]

For a microscopic object it's kinetic energy has become 4 time then how many has its wave length changed?

Water and mercury are filled in two cylindrical vessels upto same height. Both vessels have a hole in the wall near the bottom. The velocity of water and mercury coming out of the holes are v1 and v2 respectively. Thus

If momentum of an object is increased by 10% then its kinetic energy will increase by

20.A projectile is fired vertically upwards from the surface of the earth with a velocity I've,where be is the escape velocity and k

Currents flowing in a solenoid and a toroid are 2i and 6i respectively. If the number of turns per unit length is 2n and n respectively. Find the ratio of magnetic field inside the core due to solenoid and toroid.

An object is projected upwards with a velocity of 100 m/s.The time after which it will strike the ground is (g = 10ms−2)

Three uncharged capacitors of capacitance C1=1 μF, C2=2 μF and C3=3 μF are connected as shown in figure. If potential at shown points are VA=10 V; VB=25 V and VD=20 V. The potential at point O will be

18. what is equivalent weight??

For a particular MOSFET operating in the saturation region at a constant gate to source voltage (VGS), drain current (ID) is found to be 2 mA VDS=4V and 2.5 mA for VDS=8V.Then the value of λ 'is_____V−1(Whereλ is channel length modulation parameter).0.083

A transformer is used to light 100 W – 110 V lamp from 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is

An open U tube contain Mercury . When 13.6cm of water is poured into one of the arm of tube then Mercury rise in other arm from its initial level is

How do gases exert pressure?

A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad s-1. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder? What is the magnitude of angular momentum of the cylinder about its axis?

Why is angle between m and B in moving coil galvanometer =90°?

For a given length of the wire, carrying a current I, how many circular turns will produce maximum magnetic moment ?

A galvanometer has a resistance of 50 Ω and its full-scale deflection current is 50 μA. What shunt resistance should be added so that the ammeter can have a range of 0−5 mA ?

The particle changes its position with respect to time as x = (2t^3 – 3t^2 + 2t +2) m, the velocity of particle when acceleration is zero isOptions:1.5 m0.5 m2.5 m1 m

A uniform disc of mass m and radius R is projected horizontally with velocity v0 on a rough horizontal floor, so that it starts off with a purely sliding motion at t=0. After t0 seconds, it acquires a purely rolling motion as shown in figure.

Suppose a vertical tunnel is along the diameter of earth, assumed to be a sphere of uniform mass density p. If a body of mass m is thrown in this tunnel, its acceleration at a distance y from the centre is given bya) (4pi/3)Gpymb) (3pi/4)Gpymc) (4pi/3)pyd) (4pi/3)Gpy

WHY ELECTRIC LINES OF FORCES ARE PERPENDICULAR TO THE SURFACE OF CONDUCTOR?

If √1849+√0.06+x2=43.25, then x is

Two balls of masses 2 kg and 5 kg moving on a frictionless surface, collide head-on with speeds 2 m/s and 3 m/s as shown in figure. If the coefficient of restitution is 0.25, then the kinetic energy lost by the balls is

In the given arrangement, the loop is moved with constant velocity V in a uniform magnetic field B in a restricted region of width a. The time for which the emf is induced in the circuit is

in the reaction , H_2 + I_2 → 2HI , entropy increases or decreases ? explai

A sphere having charge +q is surrounded by a uncharged shell. At this time their potential difference is &quotV". Now the uncharged shell is given a charge of -3q. The new potential difference will be ??

A metal Rod of length r kept rotating with a constant angular speed Omega.A uniform and Constant Magnetic Field Is Applied Perpendicular and into the plane of Rotation.Then Find EMF induced.

the density of neon will be highest at 1)STP 2)0^0c and 2atm 3)273^0c and 1 atm 4)273^0c and 2 atm

An icebox made of 1.5 cm thick Styrofoam has dimensions 60 cm×60 cm×30 cm. It contains ice at 0∘C and is kept in a room at 40∘C. Find the rate at which the ice is melting. Latent heat of fusion of ice = 3.36×105J/kg. and thermal conductivity of Styrofoam = 0.04W/m∘C.

Identify the gates P and Q shown in the figure. Write the truth table for the combination of the gates shown.Name the equivalent gate representing this circuit and write its logic symbol.

A particle is moving in a circular path of radius 1 m.if its angular speed is 2pi rad/sec

Under isothermal condition, two soap bubbles of radii r1 and r2 coalesce to form a single bubble of radius r. The external pressure is P0. Find the surface tension of the soap in terms of the given parameters.

A body executing linear simple harmonic motion has a velocity of 3 cm/s, when its displacement is 4 cm and a velocity of 4 cm/s, when its displacement is 3 cm. What is the amplitude of oscillation?

nta rifle looses1/20thof its velocity in passing through a lank . the least no. of plank required to just stop the bulletn

Find the value of R, such that maximum power is transfereed to it.

A solid sphere rolls down from the top of an inclined plane. Its linear velocity, on reaching the bottom of the plane, is v. When the same sphere slides down (without friction) from the top of the identical inclined plane, its linear velocity on reaching the bottom is v′. The ratio v′v is -

22. A screen is placed 90cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20cm. Determine the focal length of the lens

Find the derivative of f(t)=4t−16t3+8t5.

Plane angle is obtained by dividing arc length by radius then it should be a derived quantity but why do we call it as fundamental quantity?