50278 + Interview Questions in Physics Page 65 InterviewSolution

3201.	A transverse wave travels on a taut steel wire with a velocity of v when tension in it is 2.06×104 N. When the tension is changed to T the velocity changed to v/2. The value of T is close to:
Answer» A transverse wave travels on a taut steel wire with a velocity of $v$ when tension in it is $2.06 \times 10^{4} N$ . When the tension is changed to $T$ the velocity changed to $v / 2$ . The value of $T$ is close to:

Discussion

3202.	Find the amount of work done in forming a soap film of size 5 cm×15 cm, if surface tension is 10−2 N/m.
Answer» Find the amount of work done in forming a soap film of size $5 cm \times 15 cm$ , if surface tension is $10^{- 2} N/m$ .

Discussion

3203.	The plane mirrors M1 and M2 are inclined to each other such that a ray of light incident on mirror M1 and parallel to the mirror M2 is reflected from mirror M2 parallel to the mirror M1. The angle between the two mirror is (in degrees)
Answer» The plane mirrors $M_{1}$ and $M_{2}$ are inclined to each other such that a ray of light incident on mirror $M_{1}$ and parallel to the mirror $M_{2}$ is reflected from mirror $M_{2}$ parallel to the mirror $M_{1}$ . The angle between the two mirror is (in degrees)

Discussion

3204.	A string (fixed at both ends) of length 1 m has the mass per unit length 0.1 g cm−1. What would be the frequency of vibration of this string for third overtone under the tension of 400 N ?
Answer» A string (fixed at both ends) of length $1 m$ has the mass per unit length $0.1 {g cm}^{- 1}$ . What would be the frequency of vibration of this string for third overtone under the tension of $400 N$ ?

Discussion

3205.	When characoal is prepared from a living tree, it shows a disintegration rate of 15.3 disintegratons of 14C per gram per minute. A sample from an ancient piece of charcoal shows 13C activity to be 12.3 disintegrations per gram per minute. How old is this sample? Half-life of 13C is 5730 y.
Answer» When characoal is prepared from a living tree, it shows a disintegration rate of 15.3 disintegratons of $^{14}$ C per gram per minute. A sample from an ancient piece of charcoal shows $^{13}$ C activity to be 12.3 disintegrations per gram per minute. How old is this sample? Half-life of $^{13}$ C is 5730 y.

Discussion

3206.	Photoelectric work function of a metal is 1 ev.light of wavelength 3000A^° falls on it. What is the velocity of the ejected photoelectron.
Answer» Photoelectric work function of a metal is 1 ev.light of wavelength 3000A^° falls on it. What is the velocity of the ejected photoelectron.

Discussion

3207.	A particle executes SHM of amplitude A and time period T. Find the distance travelled by the particle in the duration its phase changes by π12 to 5π12.
Answer» A particle executes $SHM$ of amplitude $A$ and time period $T$ . Find the distance travelled by the particle in the duration its phase changes by $\frac{π}{12}$ to $\frac{5 π}{12}$ .

Discussion

3208.	A block of mass M rests on a rough horizontal surface. Coefficient of friction between the block and the surface is μ. A force F=Mg acting at angle θ with the vertical side of the block pulls it. In which of the following cases the block can be pulled along the surface:- (A)†anθ≥μ (B)†an(θ/2)≥μ (C)cotθ≥μ (D)cot(θ/2)≥μ
Answer» A block of mass M rests on a rough horizontal surface. Coefficient of friction between the block and the surface is μ. A force F=Mg acting at angle θ with the vertical side of the block pulls it. In which of the following cases the block can be pulled along the surface:- (A)†anθ≥μ (B)†an(θ/2)≥μ (C)cotθ≥μ (D)cot(θ/2)≥μ

Discussion

3209.	The focal length of a convex lens made of flint glass is 15 cm. To remove its chromatic aberration, it is placed in contact with a concave lens made of crown glass. Find the focal length of the concave lens. The ratio of dispersive powers of flint glass lens to the crown glass lens is 1.5.
Answer» The focal length of a convex lens made of flint glass is $15 cm$ . To remove its chromatic aberration, it is placed in contact with a concave lens made of crown glass. Find the focal length of the concave lens. The ratio of dispersive powers of flint glass lens to the crown glass lens is $1.5$ .

Discussion

3210.	An infinitely long solid cylinder of radius R has a uniform volume charge density ρ . It has a spherical cavity of radius R2 with it's centre on the axis of the cylinder, as shown in the figure. The magnitude of the electric field at the point P, which is at a distance 2R from the axis of the cylinder, is given by the expression 23ρR16kϵ0. The value of k is
Answer» An infinitely long solid cylinder of radius $R$ has a uniform volume charge density $ρ$ . It has a spherical cavity of radius $\frac{R}{2}$ with it's centre on the axis of the cylinder, as shown in the figure. The magnitude of the electric field at the point $P$ , which is at a distance $2 R$ from the axis of the cylinder, is given by the expression $\frac{23 ρ R}{16 k ϵ_{0}}$ . The value of $k$ is

Discussion

3211.	When we jump out of a boat standing in water it moves
Answer» When we jump out of a boat standing in water it moves

Discussion

3212.	What is stationary wave
Answer» What is stationary wave

Discussion

3213.	A spaceship is launched into a circular orbit of radius R close to the surface of earth. The additional velocity to be imparted to the spaceship in the orbit to overcome the earth's gravitational pull is(Take √2=1.414 and g= acceleraton due to gravity )
Answer» A spaceship is launched into a circular orbit of radius $R$ close to the surface of earth. The additional velocity to be imparted to the spaceship in the orbit to overcome the earth's gravitational pull is (Take $\sqrt{2} = 1.414$ and $g =$ acceleraton due to gravity )

Discussion

3214.	Two balls A and B of masses 2 kg each are moving with speeds 1 m/s and 2 m/s on a frictionless surface. After colliding, the ball A returns back with speed 0.5 m/s, then the impulse of reformation of ball B is
Answer» Two balls $A$ and $B$ of masses $2 kg$ each are moving with speeds $1 m/s$ and $2 m/s$ on a frictionless surface. After colliding, the ball $A$ returns back with speed $0.5 m/s$ , then the impulse of reformation of ball $B$ is

Discussion

3215.	Show that :1/tan3A - tanA - 1/cot3A-cotA = cot 2A
Answer» Show that :1/tan3A - tanA - 1/cot3A-cotA = cot 2A

Discussion

3216.	A group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong?
Answer» A group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong?

Discussion

3217.	Why magnetic poles of magnet are not at the edges?
Answer» Why magnetic poles of magnet are not at the edges?

Discussion

3218.	There exists a spherically symmetric gravitational system of particles of radius R. Its speed V as a function of distance r(0<r<∞) from the centre of the system is represented by
Answer» There exists a spherically symmetric gravitational system of particles of radius $R$ . Its speed $V$ as a function of distance $r (0 < r < \infty)$ from the centre of the system is represented by

Discussion

3219.	The electric field 10 cm from a long wire is 2.4 kN/C. If wire carries uniform charge, what will be the field strength at 40 cm from the wire?
Answer» The electric field $10 c m$ from a long wire is $2.4 k N / C$ . If wire carries uniform charge, what will be the field strength at $40 c m$ from the wire?

Discussion

3220.	In an experiment to measure the height of a bridge by dropping stone into water underneath if the error in measurement of time is0.1 s at the end of2s then the error in estimation of height of bridge will be
Answer» In an experiment to measure the height of a bridge by dropping stone into water underneath if the error in measurement of time is0.1 s at the end of2s then the error in estimation of height of bridge will be

Discussion

3221.	If capacitive reactance is √3 times that of resistance in an AC circuit of frequency 50 Hz, then the time lag between current and voltage in milli seconds is (write until two digits after the decimal point.)
Answer» If capacitive reactance is $\sqrt{3}$ times that of resistance in an AC circuit of frequency 50 Hz, then the time lag between current and voltage in milli seconds is (write until two digits after the decimal point.)

Discussion

3222.	n identical cells , each of emf E and internal resis†an ce r , are joined in series to form a closed circuit One of the cell A is joined with reversed polarity. The potential difference across each cell except A i
Answer» n identical cells , each of emf E and internal resis†an ce r , are joined in series to form a closed circuit One of the cell A is joined with reversed polarity. The potential difference across each cell except A i

Discussion

3223.	A resonance circuit having inductance and resistance 2×10−4 H and 6.28 Ω respectively oscillates at 10 MHz frequency. The value of quantity factor of this resonator is_______
Answer» A resonance circuit having inductance and resistance $2 \times 10^{- 4} H$ and $6.28 Ω$ respectively oscillates at $10 MHz$ frequency. The value of quantity factor of this resonator is_______

Discussion

3224.	If y=(x−1)(x+2)(x−4)(x−2)(x+1), then the value of dydx at x=3 is
Answer» If $y = \frac{(x - 1) (x + 2) (x - 4)}{(x - 2) (x + 1)},$ then the value of $\frac{d y}{d x}$ at $x = 3$ is

Discussion

3225.	46. In the circuit shown below C1=10uf,C2=C3=20uf,and C4=40uf.If the charge on C1 is 20uf then potential difference between x and y is
Answer» 46. In the circuit shown below C1=10uf,C2=C3=20uf,and C4=40uf.If the charge on C1 is 20uf then potential difference between x and y is

Discussion

3226.	The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit ? (in A)(integer only)
Answer» The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit ? (in $A$ )(integer only)

Discussion

3227.	How much heat energy is gained when 5 kg of water at 20∘C is brought to its boiling point?(Specific heat of water=4.2 kJ kg−1c−1)
Answer» How much heat energy is gained when $5 k g$ of water at $20^{\circ} C$ is brought to its boiling point? $(Specific heat of water = 4.2 k J k g^{- 1} c^{- 1})$

Discussion

3228.	A cylindrical tube of uniform cross-secional area A is fitted with two air tight frictionless pistons. The pistons are connected each other by, a metallic wire. Initially, the pressure of the gas is po and temperature isT atmospheric pressure is also Po Now, thelemperatnre of the gas is increased to 2T, the tension of wire will be
Answer» A cylindrical tube of uniform cross-secional area A is fitted with two air tight frictionless pistons. The pistons are connected each other by, a metallic wire. Initially, the pressure of the gas is po and temperature isT atmospheric pressure is also Po Now, thelemperatnre of the gas is increased to 2T, the tension of wire will be

Discussion

3229.	A beam of square cross-section of side 500 mm is placed horizontally with one diagonal horizontal. It is subjected to a vertical shear force of 100 kN acting along the depth of cross section. The maximum shear stress and position of maximum shear stress from the neutral axis are respectively ?
Answer» A beam of square cross-section of side 500 mm is placed horizontally with one diagonal horizontal. It is subjected to a vertical shear force of 100 kN acting along the depth of cross section. The maximum shear stress and position of maximum shear stress from the neutral axis are respectively ?

Discussion

3230.	47 Calcium crystallizes in a face centred cubic unit cell with edge length of 0.556 nm. Calculate the density if 1) it contained 0.1% Schottky defect 2) it contained 0.1% Frenkel defect
Answer» 47 Calcium crystallizes in a face centred cubic unit cell with edge length of 0.556 nm. Calculate the density if 1) it contained 0.1% Schottky defect 2) it contained 0.1% Frenkel defect

Discussion

3231.	An infinite long straight wire is bent into a semicircle of radius R, as shonw in the figure. A current I is sent through the conductor. The magnetic field at the centre of the semicircle is :
Answer» An infinite long straight wire is bent into a semicircle of radius R, as shonw in the figure. A current I is sent through the conductor. The magnetic field at the centre of the semicircle is :

3231.

An infinite long straight wire is bent into a semicircle of radius R, as shonw in the figure. A current I is sent through the conductor. The magnetic field at the centre of the semicircle is :

Answer»

An infinite long straight wire is bent into a semicircle of radius R, as shonw in the figure. A current I is sent through the conductor. The magnetic field at the centre of the semicircle is :

Discussion

3232.	Does photocurrent depend on the incident frequency?I think it should depend as the kinetic energy of photoelectron will increase thereby increasing the charge passing through a given Cross section per unit time.
Answer» Does photocurrent depend on the incident frequency? I think it should depend as the kinetic energy of photoelectron will increase thereby increasing the charge passing through a given Cross section per unit time.

Discussion

3233.	In a region of space, the electric field is given by →E=8^i+4^j+3^k. The electric flux through a surface of area of 100 units in x−y plane is
Answer» In a region of space, the electric field is given by $\to E = 8^i + 4^j + 3^k$ . The electric flux through a surface of area of $100 units$ in $x - y$ plane is

Discussion

3234.	Work done by electrostatic force of a system of fixed charges on a 10 coulomb charge in bringing it from some reference point to a point a is 100 joules does this imply that the potential at a is 10 volts? Please explain in as simple language as possible. Thank You for the help!
Answer» Work done by electrostatic force of a system of fixed charges on a 10 coulomb charge in bringing it from some reference point to a point a is 100 joules does this imply that the potential at a is 10 volts? Please explain in as simple language as possible. Thank You for the help!

Discussion

3235.	Figure 14.30 (a) shows a spring of force constant k clampedrigidly at one end and a mass m attached to its free end. Aforce F applied at the free end stretches the spring. Figure14.30 (b) shows the same spring with both ends free and attached to amass m at either end. Each end of the spring in Fig. 14.30(b)is stretched by the same force F.(a) What is the maximum extension of the spring in the two cases?(b) If the mass in Fig. (a) and the two masses in Fig. (b) arereleased, what is the period of oscillation in each case?
Answer» Figure 14.30 (a) shows a spring of force constant k clamped rigidly at one end and a mass m attached to its free end. A force F applied at the free end stretches the spring. Figure 14.30 (b) shows the same spring with both ends free and attached to a mass m at either end. Each end of the spring in Fig. 14.30(b) is stretched by the same force F. (a) What is the maximum extension of the spring in the two cases? (b) If the mass in Fig. (a) and the two masses in Fig. (b) are released, what is the period of oscillation in each case?

3235.

Figure 14.30 (a) shows a spring of force constant k clampedrigidly at one end and a mass m attached to its free end. Aforce F applied at the free end stretches the spring. Figure14.30 (b) shows the same spring with both ends free and attached to amass m at either end. Each end of the spring in Fig. 14.30(b)is stretched by the same force F.(a) What is the maximum extension of the spring in the two cases?(b) If the mass in Fig. (a) and the two masses in Fig. (b) arereleased, what is the period of oscillation in each case?

Answer»

Figure 14.30 (a) shows a spring of force constant k clamped
rigidly at one end and a mass m attached to its free end. A
force F applied at the free end stretches the spring. Figure
14.30 (b) shows the same spring with both ends free and attached to a
mass m at either end. Each end of the spring in Fig. 14.30(b)
is stretched by the same force F.

(a) What is the maximum extension of the spring in the two cases?

(b) If the mass in Fig. (a) and the two masses in Fig. (b) are
released, what is the period of oscillation in each case?

Discussion

3236.	The displacement function S(x,t) of three sound waves 1,2 and 3 at a certain time t as marked on the curves that travel along x−axis through air. If P1,P2 and P3 represent their pressure amplitudes respectively, then the correct relation between them is:
Answer» The displacement function $S (x, t)$ of three sound waves $1, 2$ and $3$ at a certain time $t$ as marked on the curves that travel along $x - axis$ through air. If $P_{1}, P_{2} a n d P_{3}$ represent their pressure amplitudes respectively, then the correct relation between them is:

Discussion

3237.	The beam of an overall depth 250 mm and length 13 m is used in a building subjected to two different thermal environment. Temperature at top and bottom surface of the beam is 36∘ and 72∘C,α=1.5×10−5 per C∘ The vertical deflection of the beam (in m) at its span is 45.63
Answer» The beam of an overall depth 250 mm and length 13 m is used in a building subjected to two different thermal environment. Temperature at top and bottom surface of the beam is $36^{\circ}$ and $72^{\circ} C, α = 1.5 \times 10^{- 5}$ per $C^{\circ}$ The vertical deflection of the beam (in m) at its span is 45.63

Discussion

3238.	A 20∘ full depth involute spur pinion of 4 mm module and 21 teeth is to transmit 15 kW at 960 rpm. Its face width is 25 mm.Given thatthe tooth geometry factor is 0.32 and the combined effect of dynamic load and allied factors intensifying the stress is 1.5; the minimum allowable stress (in MPa) for the gear material is
Answer» A $20^{\circ}$ full depth involute spur pinion of 4 mm module and 21 teeth is to transmit 15 kW at 960 rpm. Its face width is 25 mm. Given thatthe tooth geometry factor is 0.32 and the combined effect of dynamic load and allied factors intensifying the stress is 1.5; the minimum allowable stress (in MPa) for the gear material is

Discussion

3239.	A box P and a coil Q are connected in series with an ac source of variable frequency. The emf of the source is constant at 10 V. Box P contains a capacitance of 1 μF in series with a resistance of 32 Ω. Coil Q has a self inductance of 4.9 mH and a resistance of 68 Ω in series. The frequency is adjusted so that maximum current flows in P and Q.The impedance of Q at this frequency is
Answer» A box P and a coil Q are connected in series with an ac source of variable frequency. The emf of the source is constant at $10 V$ . Box P contains a capacitance of $1 μ F$ in series with a resistance of $32 Ω$ . Coil Q has a self inductance of 4.9 mH and a resistance of $68 Ω$ in series. The frequency is adjusted so that maximum current flows in P and Q. The impedance of Q at this frequency is

Discussion

3240.	Threshold wavelength for a metal is λ0, light of wavelength incident on metal is λ02. Find deBroglie wavelength of electron with maximum K.E. ?
Answer» Threshold wavelength for a metal is $λ_{0}$ , light of wavelength incident on metal is $\frac{λ_{0}}{2}$ . Find deBroglie wavelength of electron with maximum K.E. ?

Discussion

3241.	Given that for a two-dimensional motion, velocity →v=t^i+t2^j. If particle starts from (0,0) then find out the magnitude of displacement in next 2 seconds.
Answer» Given that for a two-dimensional motion, velocity $\to v = t^i + t^{2}^j$ . If particle starts from $(0, 0)$ then find out the magnitude of displacement in next $2 seconds$ .

Discussion

3242.	Two thin lenses when in contact have power of 10D . When they are .25m apart the power reduce to 6D The focal lens of lens 1 And lens 2 is
Answer» Two thin lenses when in contact have power of 10D . When they are .25m apart the power reduce to 6D The focal lens of lens 1 And lens 2 is

Discussion

3243.	A uniform chain has a mass M and length L. It is placed on a frictionless table with length L0 hanging over the edge. The chain begins to slide down. Then, the speed v with which the end slides down from the edge is given by
Answer» A uniform chain has a mass $M$ and length $L$ . It is placed on a frictionless table with length $L_{0}$ hanging over the edge. The chain begins to slide down. Then, the speed $v$ with which the end slides down from the edge is given by

Discussion

3244.	Helium was discovered by
Answer» Helium was discovered by

Discussion

3245.	Question 14sin(45∘+θ)−cos(45∘−θ) is equal to(A) 2 cos θ(B) 0(C) 2 sin θ(D) 1
Answer» Question 14 $s i n (45^{\circ} + θ) - c o s (45^{\circ} - θ)$ is equal to (A) $2 c o s θ$ (B) 0 (C) $2 s i n θ$ (D) 1

Discussion

3246.	90.A body is projected upward with velocity v at an angle of 30 degree with the horizontal, it is at the same height at times t1 and t2 then find the velocity of projection?
Answer» 90.A body is projected upward with velocity v at an angle of 30 degree with the horizontal, it is at the same height at times t1 and t2 then find the velocity of projection?

Discussion

3247.	ntA charge q is kept at the distance d from the centre of a neutral hollow metallic sphere having radius R. Find electric field at the centre of sphere due to the induced charges on the surface of the sphere. (Kindly explain with diagram)n
Answer» ntA charge q is kept at the distance d from the centre of a neutral hollow metallic sphere having radius R. Find electric field at the centre of sphere due to the induced charges on the surface of the sphere. (Kindly explain with diagram)n

Discussion

3248.	An automobile moving at a speed of 72 km/h is brought to rest in 2 s by application of brakes. How much distance does the automobile cover in these 2 s?
Answer» An automobile moving at a speed of $72 km/h$ is brought to rest in $2 s$ by application of brakes. How much distance does the automobile cover in these $2 s$ ?

Discussion

3249.	A plane mirror makes an angle of 30 degree with the horizontal.If a vertical ray strikes the mirror,find the angle between mirror and reflected ra
Answer» A plane mirror makes an angle of 30 degree with the horizontal.If a vertical ray strikes the mirror,find the angle between mirror and reflected ra

Discussion

3250.	A charged particle, initially at rest at O, when released follows a trajectory as shown. Such a trajectory is possible in the presence of
Answer» A charged particle, initially at rest at O, when released follows a trajectory as shown. Such a trajectory is possible in the presence of

3250.

A charged particle, initially at rest at O, when released follows a trajectory as shown. Such a trajectory is possible in the presence of

Answer»

A charged particle, initially at rest at O, when released follows a trajectory as shown. Such a trajectory is possible in the presence of

Discussion

Explore topic-wise InterviewSolutions in .

A transverse wave travels on a taut steel wire with a velocity of v when tension in it is 2.06×104 N. When the tension is changed to T the velocity changed to v/2. The value of T is close to:

Find the amount of work done in forming a soap film of size 5 cm×15 cm, if surface tension is 10−2 N/m.

The plane mirrors M1 and M2 are inclined to each other such that a ray of light incident on mirror M1 and parallel to the mirror M2 is reflected from mirror M2 parallel to the mirror M1. The angle between the two mirror is (in degrees)

A string (fixed at both ends) of length 1 m has the mass per unit length 0.1 g cm−1. What would be the frequency of vibration of this string for third overtone under the tension of 400 N ?

When characoal is prepared from a living tree, it shows a disintegration rate of 15.3 disintegratons of 14C per gram per minute. A sample from an ancient piece of charcoal shows 13C activity to be 12.3 disintegrations per gram per minute. How old is this sample? Half-life of 13C is 5730 y.

Photoelectric work function of a metal is 1 ev.light of wavelength 3000A^° falls on it. What is the velocity of the ejected photoelectron.

A particle executes SHM of amplitude A and time period T. Find the distance travelled by the particle in the duration its phase changes by π12 to 5π12.

The focal length of a convex lens made of flint glass is 15 cm. To remove its chromatic aberration, it is placed in contact with a concave lens made of crown glass. Find the focal length of the concave lens. The ratio of dispersive powers of flint glass lens to the crown glass lens is 1.5.

When we jump out of a boat standing in water it moves

What is stationary wave

A spaceship is launched into a circular orbit of radius R close to the surface of earth. The additional velocity to be imparted to the spaceship in the orbit to overcome the earth's gravitational pull is(Take √2=1.414 and g= acceleraton due to gravity )

Two balls A and B of masses 2 kg each are moving with speeds 1 m/s and 2 m/s on a frictionless surface. After colliding, the ball A returns back with speed 0.5 m/s, then the impulse of reformation of ball B is

Show that :1/tan3A - tanA - 1/cot3A-cotA = cot 2A

A group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong?

Why magnetic poles of magnet are not at the edges?

There exists a spherically symmetric gravitational system of particles of radius R. Its speed V as a function of distance r(0&lt;r&lt;∞) from the centre of the system is represented by

The electric field 10 cm from a long wire is 2.4 kN/C. If wire carries uniform charge, what will be the field strength at 40 cm from the wire?

In an experiment to measure the height of a bridge by dropping stone into water underneath if the error in measurement of time is0.1 s at the end of2s then the error in estimation of height of bridge will be

If capacitive reactance is √3 times that of resistance in an AC circuit of frequency 50 Hz, then the time lag between current and voltage in milli seconds is (write until two digits after the decimal point.)

n identical cells , each of emf E and internal resis†an ce r , are joined in series to form a closed circuit One of the cell A is joined with reversed polarity. The potential difference across each cell except A i

A resonance circuit having inductance and resistance 2×10−4 H and 6.28 Ω respectively oscillates at 10 MHz frequency. The value of quantity factor of this resonator is_______

If y=(x−1)(x+2)(x−4)(x−2)(x+1), then the value of dydx at x=3 is

46. In the circuit shown below C1=10uf,C2=C3=20uf,and C4=40uf.If the charge on C1 is 20uf then potential difference between x and y is

The circuit has two oppositely connected ideal diodes in parallel. What is the current flowing in the circuit ? (in A)(integer only)

How much heat energy is gained when 5 kg of water at 20∘C is brought to its boiling point?(Specific heat of water=4.2 kJ kg−1c−1)

A beam of square cross-section of side 500 mm is placed horizontally with one diagonal horizontal. It is subjected to a vertical shear force of 100 kN acting along the depth of cross section. The maximum shear stress and position of maximum shear stress from the neutral axis are respectively ?

47 Calcium crystallizes in a face centred cubic unit cell with edge length of 0.556 nm. Calculate the density if 1) it contained 0.1% Schottky defect 2) it contained 0.1% Frenkel defect

An infinite long straight wire is bent into a semicircle of radius R, as shonw in the figure. A current I is sent through the conductor. The magnetic field at the centre of the semicircle is :

Does photocurrent depend on the incident frequency?I think it should depend as the kinetic energy of photoelectron will increase thereby increasing the charge passing through a given Cross section per unit time.

In a region of space, the electric field is given by →E=8^i+4^j+3^k. The electric flux through a surface of area of 100 units in x−y plane is

Work done by electrostatic force of a system of fixed charges on a 10 coulomb charge in bringing it from some reference point to a point a is 100 joules does this imply that the potential at a is 10 volts? Please explain in as simple language as possible. Thank You for the help!

The displacement function S(x,t) of three sound waves 1,2 and 3 at a certain time t as marked on the curves that travel along x−axis through air. If P1,P2 and P3 represent their pressure amplitudes respectively, then the correct relation between them is:

The beam of an overall depth 250 mm and length 13 m is used in a building subjected to two different thermal environment. Temperature at top and bottom surface of the beam is 36∘ and 72∘C,α=1.5×10−5 per C∘ The vertical deflection of the beam (in m) at its span is 45.63

Threshold wavelength for a metal is λ0, light of wavelength incident on metal is λ02. Find deBroglie wavelength of electron with maximum K.E. ?

Given that for a two-dimensional motion, velocity →v=t^i+t2^j. If particle starts from (0,0) then find out the magnitude of displacement in next 2 seconds.

Two thin lenses when in contact have power of 10D . When they are .25m apart the power reduce to 6D The focal lens of lens 1 And lens 2 is

A uniform chain has a mass M and length L. It is placed on a frictionless table with length L0 hanging over the edge. The chain begins to slide down. Then, the speed v with which the end slides down from the edge is given by

Helium was discovered by

Question 14sin(45∘+θ)−cos(45∘−θ) is equal to(A) 2 cos θ(B) 0​​​​​​​(C) 2 sin θ​​​​​​​(D) 1​​​​​​​

90.A body is projected upward with velocity v at an angle of 30 degree with the horizontal, it is at the same height at times t1 and t2 then find the velocity of projection?

ntA charge q is kept at the distance d from the centre of a neutral hollow metallic sphere having radius R. Find electric field at the centre of sphere due to the induced charges on the surface of the sphere. (Kindly explain with diagram)n

An automobile moving at a speed of 72 km/h is brought to rest in 2 s by application of brakes. How much distance does the automobile cover in these 2 s?

A plane mirror makes an angle of 30 degree with the horizontal.If a vertical ray strikes the mirror,find the angle between mirror and reflected ra

A charged particle, initially at rest at O, when released follows a trajectory as shown. Such a trajectory is possible in the presence of

There exists a spherically symmetric gravitational system of particles of radius R. Its speed V as a function of distance r(0<r<∞) from the centre of the system is represented by

Question 14sin(45∘+θ)−cos(45∘−θ) is equal to(A) 2 cos θ(B) 0(C) 2 sin θ(D) 1