13753 + Interview Questions in Physics QA in Physics

1.	2. Apply Gauss theorem to show that for a spherical shell, the electric field inside the shellvanishes whereas outside it, the field is as if all the charge had been concentrated at thecentre.
Answer» Consider a thin spherical shell of radius R with a positive charge q distributed uniformly on the surface. As the charge is uniformly distributed, the electric field is symmetrical and directed radially outward (positive charge) in all directions. The magnitude of electric field is the same at all points that are equidistant from the shell. All such points lie on a sphere. So the symmetry here is spherical symmetry. Hence we shall use a spherical Gaussian surface to find the electric flux and hence the magnitude of electric field at a point inside and outside of the charged shell.

Discussion

2.	\begin{array} { l } { \text { A uniform solid sphere of mass } M \text { and radius a is } } \\ { \text { surrounded symmetrically by a uniform thin spherical } } \\ { \text { shell of equal mass and radius } 2 \text { a. Find the gravitational } } \\ { \text { field at a distance (a) } \frac { 3 } { 2 } a \text { from the centre, (b) } \frac { 5 } { 2 } a \text { from } } \\ { \text { the centre. } } \end{array}
Answer»

Discussion

3.	Gravitational field ia uniform, the gravitational PDface of a planet and point 100 m aboveKg. The work done in moving a mass50 J/5 kg from surface to a point 10 m above is1)5 J2) 25J3)2.5J4) 50 J
Answer» The potential per unit mass is: U/m = a·h 50 joule/kg = a·(100 m) 1/2 joule/kg-m = a Work to lift a mass m to a height h is: W = F·d = ma·h m = 5 kg a = 1/2 m/s2 h = 10 m W = 25 J

3.

Gravitational field ia uniform, the gravitational PDface of a planet and point 100 m aboveKg. The work done in moving a mass50 J/5 kg from surface to a point 10 m above is1)5 J2) 25J3)2.5J4) 50 J

Answer»

The potential per unit mass is:

U/m = a·h

50 joule/kg = a·(100 m)

1/2 joule/kg-m = a

Work to lift a mass m to a height h is:

W = F·d = ma·h

m = 5 kg

a = 1/2 m/s2

h = 10 m

W = 25 J

Discussion

4.	(3) b0%A gas is compressed at a constant pressure of50 N/m2 from a volume of 10 m3 to a volume of4m3. Energy of 100 J then added to the gas byheating. Its internal energy isIncreased by 400 J (2) Increased by 200 JDecreased by 200 J3 Increased by 100 J (4)
Answer»

Discussion

5.	अर. AR~ »\_‘M 3o VSRR AR A टतल वO o 1o =3e लकD - किस िियन o दें &T किस वे
Answer» Ans :- दर्पण एक वस्तु है जो इस तरह से प्रकाश को प्रतिबिंबित करती है कि, तरंगदैर्ध्य की कुछ सीमाओं में घटना प्रकाश के लिए, परिलक्षित प्रकाश मूल प्रकाश की कई या अधिकतर भौतिक विशेषताओं को संरक्षित करता है, जिसे प्रतिबिंब कहा जाता है।

Discussion

6.	State the universal law of gravitation.
Answer» The universal law of gravitationstates that every object in the universe attracts every other object with a force called the gravitational force. The force acting between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. thanks

6.

State the universal law of gravitation.

Answer»

The universal law of gravitationstates that every object in the universe attracts every other object with a force called the gravitational force. The force acting between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

thanks

Discussion

7.	state Newton's universal law of gravition
Answer»

Discussion

8.	1 State the universal law of gravitation.
Answer»

Discussion

9.	vmoleculan-weight-of-Sulthunousеeld
Answer» Molecular Formula: H2SO3or H2O3S. Molecular Weight: 82.073 g/mol. Molecular Formula:H2SO3or H2O3S Molecular Weight:82.073 g/mol

9.

vmoleculan-weight-of-Sulthunousеeld

Answer»

Molecular Formula: H2SO3or H2O3S. Molecular Weight: 82.073 g/mol.

Molecular Formula:H2SO3or H2O3S

Molecular Weight:82.073 g/mol

Discussion

10.	State an derive the universal law of Gravitation
Answer» Newton's law of universal gravitation states that every particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers

Discussion

11.	) The moment of inertia of a thin uniform rod of mass M and length L, about an axis passing through apoint midway between the centre and one end, perpendicular to its length is
Answer»

Discussion

12.	explain the newtons third law
Answer» Every action has equal and opposite reaction Newton's Third Law of Motion states, "For every action, there is an equal and opposite reaction."

12.

explain the newtons third law

Answer»

Every action has equal and opposite reaction

Newton's Third Law of Motion states, "For every action, there is an equal and opposite reaction."

Discussion

13.	state newtons universal law of gravitation
Answer» Newton's law of universal gravitationstates that a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

Discussion

14.	Weiteofand derive Newtons lawgravitestion.
Answer»

Discussion

15.	A particle siarts SHM from thee mavinuem speed, ts displacement y ismean position. Its ampliude is A and tme period is T At the time when ts speed s hait ofAV328)2Ac)2
Answer»

Discussion

16.	Q3.Suppose ã is a vector of magnitude 4.5 units due north. What is the vectorI. 3ã,
Answer» Thank you so much

Discussion

17.	Give examples to show that friction is both a friend and a foe.
Answer»

Discussion

18.	What should be the minimum value of refractive indexof the material of prism for reflections to take place asshown in fig.45) 1.4b) 1.7c) 2.7d) 1.2
Answer»

Discussion

19.	= 6 2 x 106. Figure (26-W3) shows a process ABCA performed on anideal gas. Find the net heat given to the system duringthe process.Vat
Answer»

Discussion

20.	A thick straight wire of length am isfixed at its midpoint and then bent in theform of a circle. The shift in its centre ofmass isa) tm b)0.5m c)2m d m
Answer» opsonin c 2m is the right answer Answer:b)0.5mExplanation:When the wire is bent in the form of the circle the center of mass of the wire shifts to the center of the wire. Thus, the shift in center of mass of the wire is equal to the radius of the circular wire. Suppose the radius of the circular wire is ‘x’. The circumference of the wire will be 2πx. Since, length of the wire is π, so, π = 2πx => x = 0.5 m. This is the shift in origin of the center of mass of the wire.

20.

A thick straight wire of length am isfixed at its midpoint and then bent in theform of a circle. The shift in its centre ofmass isa) tm b)0.5m c)2m d m

Answer»

opsonin c 2m is the right answer

Answer:b)0.5mExplanation:When the wire is bent in the form of the circle the center of mass of the wire shifts to the center of the wire. Thus, the shift in center of mass of the wire is equal to the radius of the circular wire.

Suppose the radius of the circular wire is ‘x’.

The circumference of the wire will be 2πx.

Since, length of the wire is π, so, π = 2πx

=> x = 0.5 m.

This is the shift in origin of the center of mass of the wire.

Discussion

21.	The tension inthe string inthe pulley system shownin figure is18·60㎏
Answer» so the answer is (2×6×10×10)/(6+10) = 1200/16 = 75

Discussion

22.	(31) Speed of particle is given by V- a-+c+tAmong following [MP LT-2] is dimensionalformula of(a)acab(d)
Answer» The dimension of a should be of velocity - L/T The dimension of b should be of distance , so Land The dimension of C should be of time = T so, ac wi has dimension of L/T.T = LT-². option A.

22.

(31) Speed of particle is given by V- a-+c+tAmong following [MP LT-2] is dimensionalformula of(a)acab(d)

Answer»

The dimension of a should be of velocity - L/T The dimension of b should be of distance , so Land The dimension of C should be of time = T

so, ac wi has dimension of L/T.T = LT-².

option A.

Discussion

23.	Temperature at which the velocity of sound in 0, is thesame as that on N, at 27°C is approximately(1)60°C73.(2) 80°C(4)27°C3) 70°C
Answer»

Discussion

24.	0Calculate the total number of electrons present in 1-4g of dinitrogen gas.
Answer»

Discussion

25.	A hollow cylinder has mass M, outside radius R2 and inside radius R1. Its moment of inertia about anaxis parallel to its symmetry axis and tangential to the outer surface is equal to(A) 쓸 (R22 + R?)(B) 블 (R22-R12)(C)블(R2 + Rıf(D)쓸(3R22 + R12)4
Answer» The total energy in the system is given by T = 1/2 m2 Vo^2 + 1/2 m1 Vo^2 + 1/2 I wo^2= 1/2 m2 Vf^2 + 1/2 m1 Vf^2 + 1/2 I wf^2 - m1gd + uk m2g d where Vo,Vf are the initial and final velocity of the blocks, wo/wf are the initial and finalangular velocityof the pulley, I is themoment of inertiaof the pulley. w is related to V as Vo = R2 wo and Vf = R2 wf. Also, the moment of inertia is given by I = 1/2 m (R2^2 + R1^2)

25.

A hollow cylinder has mass M, outside radius R2 and inside radius R1. Its moment of inertia about anaxis parallel to its symmetry axis and tangential to the outer surface is equal to(A) 쓸 (R22 + R?)(B) 블 (R22-R12)(C)블(R2 + Rıf(D)쓸(3R22 + R12)4

Answer»

The total energy in the system is given by

T = 1/2 m2 Vo^2 + 1/2 m1 Vo^2 + 1/2 I wo^2= 1/2 m2 Vf^2 + 1/2 m1 Vf^2 + 1/2 I wf^2 - m1gd + uk m2g d

where Vo,Vf are the initial and final velocity of the blocks, wo/wf are the initial and finalangular velocityof the pulley, I is themoment of inertiaof the pulley. w is related to V as

Vo = R2 wo and Vf = R2 wf.

Also, the moment of inertia is given by

I = 1/2 m (R2^2 + R1^2)

Discussion

26.	2x+3y =5
Answer» Please post the complete question

Discussion

27.	In the given figure, the capacitors C1, C3, C4, C5C1C2CaC5have a capacitance 4 μF each. If the capacitor C2has a capacitance 10 μF, then effective capacitancebetween A and B will be
Answer»

Discussion

28.	C1=1μFwithstands rnaximum volta V1=6kV and C2=2μFwithstands maximum voltage ,What voltage will the series combination of these two capacitors withstand?
Answer»

Discussion

29.	Three capacitors of capacity Cl , C2 , Cconnected in series. Their total capacity will be3 are(A) C1 + C2 + C3)(Cl+C2+C3)Cnone of these-1
Answer»

Discussion

30.	SECTION-CDraw the molecular orbital diagram for oxygen molecule (O2) and calculate bond order
Answer» wrong

Discussion

31.	1.1. What is the force between two small charged spkereshaving charges of2x 107 Cand 3x10-7 С placed 30 cmnaportin air ?
Answer»

Discussion

32.	57.The circuit illustrates a typical application of the JK flip-flops.What does this represent?HIGHO HIGHQBCLOCKCLKCLKPULSE
Answer» It will show the clock frequency as the output of first flip flop is fed to diffrentiated level of first.

Discussion

33.	(c) A convex lens of focal length 25 cm ond #concave lens of focal length 10 m rplaced in close contact with each other Celculate the lens power of this combbinationstion
Answer» Power = 1/f where f is focal length in meter p1 = 100/25= 4 (for convex lens) p2 = -100/10 = -10 (power is negative because focal length of concave lens is negative) Now,Resultant power = p1+p2 = 4+(-10)= -6

33.

(c) A convex lens of focal length 25 cm ond #concave lens of focal length 10 m rplaced in close contact with each other Celculate the lens power of this combbinationstion

Answer»

Power = 1/f where f is focal length in meter p1 = 100/25= 4 (for convex lens)

p2 = -100/10 = -10 (power is negative because focal length of concave lens is negative)

Now,Resultant power = p1+p2 = 4+(-10)= -6

Discussion

34.	6.a) Determine the electric potential energy of a system consisting of two charges 7 LCand-2 c (and with no external field) placed al-Sem, 0, 0) and (9cm, 0, 0).b) How much work is required to separate emocrages Infinity away from prichother?
Answer»

Discussion

35.	Godty Covers 2ind Seaarl ond 2er
Answer»

Discussion

36.	54. A 1 kg mass falls from a height of 10 m into a sand box. What is the speed of the mass just before hittingsand box? If it travels a distance of 2 cm into the sand before coming to rest, what is the average retarding for(1) 12 m/sec and 3600 N(3) 16 m/sec and 6400 N(2) 14 m/sec and 4900 N(4) 18 m/sec and 8100 Ntirnlhu with kinetic enery of 490 J. lif the acceleration due to g
Answer»

Discussion

37.	A particle of mass 2 kg travels according to equation S 3t +2t. Find the work done in 3 second of its119.motion.(1)6889 J(2) 6885 J(3) 1782 J(4) none of these
Answer» s=3t³+2tdifferentiating s with respect to t to get velocityv=ds/dt=d(3t³+2t)/dt=9t²+2 in third second, v=9(3)²+2=83So, work done in 3 second of motion is,KE=(1/2)mv²KE=0.5284*83KE=6889Jhence correct answer is (A)

37.

A particle of mass 2 kg travels according to equation S 3t +2t. Find the work done in 3 second of its119.motion.(1)6889 J(2) 6885 J(3) 1782 J(4) none of these

Answer»

s=3t³+2tdifferentiating s with respect to t to get velocityv=ds/dt=d(3t³+2t)/dt=9t²+2

in third second, v=9(3)²+2=83So, work done in 3 second of motion is,KE=(1/2)*m*v²KE=0.5*2*84*83KE=6889Jhence correct answer is (A)

Discussion

38.	C.Define friction. Also give the SI unit of friction.
Answer» The force that resists motion of a body is called friction . It produces heat . For example----in winters when we rub our hands against each other ( motion ) , it produces friction which produces heat . It is due to force of friction that when we apply brakes in cars , the tyres are able to stop . As it is a kind of force , it's SI unit is that of force i e ---- Newtons . the resistance that one surface or object encounter when moving over another . si unit of friction is newton Friction PHYSICS WRITTEN BY: The Editors of Encyclopaedia Britannica See Article History Friction QUICK FACTS RELATED TOPICS Matter Wear Viscosity Dry damping Coefficient of friction Stick-slip friction Static friction Kinetic friction Internal friction Rolling friction Friction,forcethat resists the sliding or rolling of onesolidobject over another. Frictional forces, such as the traction needed to walk without slipping, may bebeneficial, but they also present a great measure of opposition tomotion. About 20 percent of the enginepowerofautomobilesis consumed in overcoming frictional forces in the moving parts. READ MORE ON THIS TOPIC ocean current: Frictional forces Movement of water through the oceans is slowed by friction, with surrounding fluid moving at a different… The major cause of friction betweenmetalsappears to be the forces of attraction, known asadhesion, between the contact regions of the surfaces, which are always microscopically irregular. Friction arises from shearing these “welded” junctions and from the action of the irregularities of the harder surface plowing across the softer surface. Two simple experimental facts characterize the friction of sliding solids. First, the amount of friction is nearly independent of the area of contact. If a brick is pulled along a table, the frictional force is the same whether the brick is lying flat or standing on end. Second, friction is proportional to the load or weight that presses the surfaces together. If a pile of three bricks is pulled along a table, the friction is three times greater than if one brick is pulled. Thus, the ratio of frictionFto loadLis constant. This constant ratio is called thecoefficient of frictionand is usually symbolized by the Greek letter mu (μ). Mathematically,μ=F/L.Because both friction and load are measured in units of force (such aspoundsornewtons), the coefficient of friction is dimensionless. The value of the coefficient of friction for a case of one or more bricks sliding on a clean wooden table is about 0.5, which implies that a force equal to half the weight of the bricks is required just to overcome friction in keeping the bricks moving along at a constant speed. The frictional force itself is directed oppositely to the motion of the object. Because the friction thus far described arises between surfaces in relative motion, it is calledkinetic friction. Static friction, in contrast, acts between surfaces at rest with respect to each other. The value of static friction varies between zero and the smallest force needed to start motion. This smallest force required to start motion, or to overcome static friction, is always greater than the force required to continue the motion, or to overcome kinetic friction. Like what you’re reading?Start your free trial today for unlimited access to Britannica. Rolling friction occurs when a wheel, ball, or cylinder rolls freely over a surface, as in ball and roller bearings. The main source of friction in rolling appears to bedissipationofenergyinvolved indeformationof the objects. If a hard ball is rolling on a level surface, the ball is somewhat flattened and the level surface somewhat indented in the regions in contact. The elastic deformation or compression produced at the leading section of the area in contact is a hindrance to motion that is not fully compensated as the substances spring back to normal shape at the trailing section. The internal losses in the two substances are similar to those that keep a ball from bouncing back to the level from which it is dropped. Coefficients of sliding friction are generally 100 to 1,000 times greater than coefficients of rolling friction for corresponding materials. This advantage was realized historically with the transition fromsledgetowheel. (Seemechanics.) This article was most recently revised and updated byErik Gregersen, Senior Editor. LEARN MOREin these related Britannica articles: ocean current: Frictional forces Movement of water through the oceans is slowed by friction, with surrounding fluid moving at a different… ship: Design of the hull Frictional resistance is proportional to the product of water density, area of contact with the water,… mechanics: Damped and forced oscillations …produced by forces such as friction and viscosity. These forces are known collectively as dissipative… mechanics: Rotation about a moving axis In addition to gravity, friction plays an essential role. The force of friction, written as f,… electromagnetism: Emergence of the modern sciences of electricity and magnetism …between two objects charged by friction and showed that frictional electricity occurs in many common… HISTORY AT YOUR FINGERTIPS Sign up here to see what happenedOn This Day, every day in your inbox! By signing up, you agree to ourPrivacy Notice. MORE ABOUT

38.

C.Define friction. Also give the SI unit of friction.

Answer»

The force that resists motion of a body is called friction . It produces heat . For example----in winters when we rub our hands against each other ( motion ) , it produces friction which produces heat . It is due to force of friction that when we apply brakes in cars , the tyres are able to stop .

As it is a kind of force , it's SI unit is that of force i e ---- Newtons .

the resistance that one surface or object encounter when moving over another .

si unit of friction is newton

Friction

PHYSICS

WRITTEN BY:

The Editors of Encyclopaedia Britannica

See Article History

Friction

QUICK FACTS

READ MORE ON THIS TOPIC

ocean current: Frictional forces

Movement of water through the oceans is slowed by friction, with surrounding fluid moving at a different…

The major cause of friction betweenmetalsappears to be the forces of attraction, known asadhesion, between the contact regions of the surfaces, which are always microscopically irregular. Friction arises from shearing these “welded” junctions and from the action of the irregularities of the harder surface plowing across the softer surface.

Two simple experimental facts characterize the friction of sliding solids. First, the amount of friction is nearly independent of the area of contact. If a brick is pulled along a table, the frictional force is the same whether the brick is lying flat or standing on end. Second, friction is proportional to the load or weight that presses the surfaces together. If a pile of three bricks is pulled along a table, the friction is three times greater than if one brick is pulled. Thus, the ratio of frictionFto loadLis constant. This constant ratio is called thecoefficient of frictionand is usually symbolized by the Greek letter mu (μ). Mathematically,μ=F/L.Because both friction and load are measured in units of force (such aspoundsornewtons), the coefficient of friction is dimensionless. The value of the coefficient of friction for a case of one or more bricks sliding on a clean wooden table is about 0.5, which implies that a force equal to half the weight of the bricks is required just to overcome friction in keeping the bricks moving along at a constant speed. The frictional force itself is directed oppositely to the motion of the object. Because the friction thus far described arises between surfaces in relative motion, it is calledkinetic friction.

Static friction, in contrast, acts between surfaces at rest with respect to each other. The value of static friction varies between zero and the smallest force needed to start motion. This smallest force required to start motion, or to overcome static friction, is always greater than the force required to continue the motion, or to overcome kinetic friction.

Like what you’re reading?Start your free trial today for unlimited access to Britannica.

Rolling friction occurs when a wheel, ball, or cylinder rolls freely over a surface, as in ball and roller bearings. The main source of friction in rolling appears to bedissipationofenergyinvolved indeformationof the objects. If a hard ball is rolling on a level surface, the ball is somewhat flattened and the level surface somewhat indented in the regions in contact. The elastic deformation or compression produced at the leading section of the area in contact is a hindrance to motion that is not fully compensated as the substances spring back to normal shape at the trailing section. The internal losses in the two substances are similar to those that keep a ball from bouncing back to the level from which it is dropped. Coefficients of sliding friction are generally 100 to 1,000 times greater than coefficients of rolling friction for corresponding materials. This advantage was realized historically with the transition fromsledgetowheel. (Seemechanics.)

This article was most recently revised and updated byErik Gregersen, Senior Editor.

LEARN MOREin these related Britannica articles:

ocean current: Frictional forces

Movement of water through the oceans is slowed by friction, with surrounding fluid moving at a different…

ship: Design of the hull

Frictional resistance is proportional to the product of water density, area of contact with the water,…

mechanics: Damped and forced oscillations

…produced by forces such as friction and viscosity. These forces are known collectively as dissipative…

mechanics: Rotation about a moving axis

In addition to gravity, friction plays an essential role. The force of friction, written as f,…

electromagnetism: Emergence of the modern sciences of electricity and magnetism

…between two objects charged by friction and showed that frictional electricity occurs in many common…

HISTORY AT YOUR FINGERTIPS

Sign up here to see what happenedOn This Day, every day in your inbox!

By signing up, you agree to ourPrivacy Notice.

MORE ABOUT

Discussion

39.	. A boat loaded with stone floatson the surface of pool of water.When the stone is transferredfrom the boat to water in thepool, the water level in the pool(a) rises(b) falls
Answer»

Discussion

40.	If the radius of a sphere is measured as 9 em with an error of 0-03 em, then find the approximateerror in calculating its surface areaAICBSE 20111
Answer»

Discussion

41.	Two cells of emfs ει & ε2 and internal resistances r1 & r2 respectively are connected inparallel. Obtain expressions for the equivalent resistance and emf of the combination
Answer» We have two cells E1 and E2 with internal resistance r1 and r2 connected in parallel with a resistor R.Let, I1 and I2 be the current through E1 and E2 respectively.By applying KCL(Kirchhoff's Current Law),I = I1 + I2Let there resultant EMF is Eeff and resultant resistance be Req.By KVL(Kirchhoff's Voltage Law)Potential across R = Eeff - IReqPotential across upper branch = E1 - Ir1Potential across Lower Branch = E2 - Ir2After solving we will getEeff = (E1/r1 + E2/r2)ReqandReq = r1*r2/(r1 +r2) Eequa=(E1R2+E2R2)/(R1+R2)

41.

Two cells of emfs ει & ε2 and internal resistances r1 & r2 respectively are connected inparallel. Obtain expressions for the equivalent resistance and emf of the combination

Answer»

We have two cells E1 and E2 with internal resistance r1 and r2 connected in parallel with a resistor R.Let, I1 and I2 be the current through E1 and E2 respectively.By applying KCL(Kirchhoff's Current Law),I = I1 + I2Let there resultant EMF is Eeff and resultant resistance be Req.By KVL(Kirchhoff's Voltage Law)Potential across R = Eeff - I*ReqPotential across upper branch = E1 - I*r1Potential across Lower Branch = E2 - I*r2After solving we will getEeff = (E1/r1 + E2/r2)*ReqandReq = r1*r2/(r1 +r2)

Eequa=(E1R2+E2R2)/(R1+R2)

Discussion

42.	A stone of mass 0.1 kg tied to one end of a string1.0 m long is revolved in a horizontal circle at therate of 10/t revolution per second. Calculate thetension of the string?(A) 30 N(C) 50 N(B) 40 N(D) 60 N
Answer»

Discussion

43.	13.What do you mean by resistance of a conductor.Find the effective resistance in between points A and B in given circuit14 ΩA B5Ω9&2 48 (115 210Ω20 Ω6 28 52
Answer»

Discussion

44.	A body weighing 0.4 kg is whirled in a vertical circle making 2 revolution per secIf the radius of the circle is 12 meter. Find the tension in the string, when body is),at the bottom of the circle. (ii) atthe top of the circle.Q19-3,
Answer»

Discussion

45.	11. The specific resistance of metallic conductor is dependsm the metallic conductor(a) Length(c) Arca(b) TemperaturedyAll of these
Answer» option A

Discussion

46.	Two parallel resistances of 6 ohm and 12 ohm are compared with a known resistance of onnonmetre bridge. The balance point on the wire from the parallel resistors endis (in c.m.331y 662b) 40Il-9
Answer»

Discussion

47.	Calculate the change in momentum of a body weighing 5 kg when its velocitydecreases from 20 m/s to 0.20 m/s.
Answer»

Discussion

48.	How many bulbs of resistance 6 9 should bejoined in parallel to draw a current of 2 A from abattery of 3 V?
Answer» ___________________________ ▶️Suppose n resistances of 6 ohm are connected in parallel and the resultant resistance=R ▶️1/R=n/6=>R=6/n ▶️Now Current I=2 A,Voltage V=3 volts ▶️By ohm's law V=IR ▶️3=2x6/n ▶️n=4 ▶️▶️Hence 4 bulbs are connected in parallel. 3 is the correct answer 3 is the correct answer of the given question 3 bulbs, that's the right answer of this question

48.

How many bulbs of resistance 6 9 should bejoined in parallel to draw a current of 2 A from abattery of 3 V?

Answer»

___________________________

▶️Suppose n resistances of 6 ohm are connected in parallel and the resultant resistance=R

▶️1/R=n/6=>R=6/n

▶️Now Current I=2 A,Voltage V=3 volts

▶️By ohm's law V=IR

▶️3=2x6/n

▶️n=4

▶️▶️Hence 4 bulbs are connected in parallel.

3 is the correct answer

3 is the correct answer of the given question

3 bulbs, that's the right answer of this question

Discussion

49.	prove that the residual mass M of rocket decreases and velocity V of rocket increases with the time during the flight of rocket
Answer»

Discussion

50.	How is the colour of sky seen to an astronaut?(1) Green(2) Blue(3) Indigo(4) Darken
Answer» Sky appears dark to an astronaut

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

2. Apply Gauss theorem to show that for a spherical shell, the electric field inside the shellvanishes whereas outside it, the field is as if all the charge had been concentrated at thecentre.

Gravitational field ia uniform, the gravitational PDface of a planet and point 100 m aboveKg. The work done in moving a mass50 J/5 kg from surface to a point 10 m above is1)5 J2) 25J3)2.5J4) 50 J

(3) b0%A gas is compressed at a constant pressure of50 N/m2 from a volume of 10 m3 to a volume of4m3. Energy of 100 J then added to the gas byheating. Its internal energy isIncreased by 400 J (2) Increased by 200 JDecreased by 200 J3 Increased by 100 J (4)

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State the universal law of gravitation.

state Newton's universal law of gravition

1 State the universal law of gravitation.

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State an derive the universal law of Gravitation

) The moment of inertia of a thin uniform rod of mass M and length L, about an axis passing through apoint midway between the centre and one end, perpendicular to its length is

explain the newtons third law

state newtons universal law of gravitation

Weiteofand derive Newtons lawgravitestion.

A particle siarts SHM from thee mavinuem speed, ts displacement y ismean position. Its ampliude is A and tme period is T At the time when ts speed s hait ofAV328)2Ac)2

Q3.Suppose ã is a vector of magnitude 4.5 units due north. What is the vectorI. 3ã,

Give examples to show that friction is both a friend and a foe.

What should be the minimum value of refractive indexof the material of prism for reflections to take place asshown in fig.45) 1.4b) 1.7c) 2.7d) 1.2

= 6 2 x 106. Figure (26-W3) shows a process ABCA performed on anideal gas. Find the net heat given to the system duringthe process.Vat

A thick straight wire of length am isfixed at its midpoint and then bent in theform of a circle. The shift in its centre ofmass isa) tm b)0.5m c)2m d m

The tension inthe string inthe pulley system shownin figure is18·60㎏

(31) Speed of particle is given by V- a-+c+tAmong following [MP LT-2] is dimensionalformula of(a)acab(d)

Temperature at which the velocity of sound in 0, is thesame as that on N, at 27°C is approximately(1)60°C73.(2) 80°C(4)27°C3) 70°C

0Calculate the total number of electrons present in 1-4g of dinitrogen gas.

A hollow cylinder has mass M, outside radius R2 and inside radius R1. Its moment of inertia about anaxis parallel to its symmetry axis and tangential to the outer surface is equal to(A) 쓸 (R22 + R?)(B) 블 (R22-R12)(C)블(R2 + Rıf(D)쓸(3R22 + R12)4

2x+3y =5

In the given figure, the capacitors C1, C3, C4, C5C1C2CaC5have a capacitance 4 μF each. If the capacitor C2has a capacitance 10 μF, then effective capacitancebetween A and B will be

C1=1μFwithstands rnaximum volta V1=6kV and C2=2μFwithstands maximum voltage ,What voltage will the series combination of these two capacitors withstand?

Three capacitors of capacity Cl , C2 , Cconnected in series. Their total capacity will be3 are(A) C1 + C2 + C3)(Cl+C2+C3)Cnone of these-1

SECTION-CDraw the molecular orbital diagram for oxygen molecule (O2) and calculate bond order

1.1. What is the force between two small charged spkereshaving charges of2x 107 Cand 3x10-7 С placed 30 cmnaportin air ?

57.The circuit illustrates a typical application of the JK flip-flops.What does this represent?HIGHO HIGHQBCLOCKCLKCLKPULSE

(c) A convex lens of focal length 25 cm ond #concave lens of focal length 10 m rplaced in close contact with each other Celculate the lens power of this combbinationstion

6.a) Determine the electric potential energy of a system consisting of two charges 7 LCand-2 c (and with no external field) placed al-Sem, 0, 0) and (9cm, 0, 0).b) How much work is required to separate emocrages Infinity away from prichother?

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A particle of mass 2 kg travels according to equation S 3t +2t. Find the work done in 3 second of its119.motion.(1)6889 J(2) 6885 J(3) 1782 J(4) none of these

C.Define friction. Also give the SI unit of friction.

. A boat loaded with stone floatson the surface of pool of water.When the stone is transferredfrom the boat to water in thepool, the water level in the pool(a) rises(b) falls

If the radius of a sphere is measured as 9 em with an error of 0-03 em, then find the approximateerror in calculating its surface areaAICBSE 20111

Two cells of emfs ει &amp; ε2 and internal resistances r1 &amp; r2 respectively are connected inparallel. Obtain expressions for the equivalent resistance and emf of the combination

A stone of mass 0.1 kg tied to one end of a string1.0 m long is revolved in a horizontal circle at therate of 10/t revolution per second. Calculate thetension of the string?(A) 30 N(C) 50 N(B) 40 N(D) 60 N

13.What do you mean by resistance of a conductor.Find the effective resistance in between points A and B in given circuit14 ΩA B5Ω9&amp;2 48 (115 210Ω20 Ω6 28 52

A body weighing 0.4 kg is whirled in a vertical circle making 2 revolution per secIf the radius of the circle is 12 meter. Find the tension in the string, when body is),at the bottom of the circle. (ii) atthe top of the circle.Q19-3,

11. The specific resistance of metallic conductor is dependsm the metallic conductor(a) Length(c) Arca(b) TemperaturedyAll of these

Two parallel resistances of 6 ohm and 12 ohm are compared with a known resistance of onnonmetre bridge. The balance point on the wire from the parallel resistors endis (in c.m.331y 662b) 40Il-9

Calculate the change in momentum of a body weighing 5 kg when its velocitydecreases from 20 m/s to 0.20 m/s.

How many bulbs of resistance 6 9 should bejoined in parallel to draw a current of 2 A from abattery of 3 V?

prove that the residual mass M of rocket decreases and velocity V of rocket increases with the time during the flight of rocket

How is the colour of sky seen to an astronaut?(1) Green(2) Blue(3) Indigo(4) Darken

अर. AR~ »\_‘M 3o VSRR AR A टतल वO o 1o =3e लकD - किस िियन o दें &T किस वे

Two cells of emfs ει & ε2 and internal resistances r1 & r2 respectively are connected inparallel. Obtain expressions for the equivalent resistance and emf of the combination

13.What do you mean by resistance of a conductor.Find the effective resistance in between points A and B in given circuit14 ΩA B5Ω9&2 48 (115 210Ω20 Ω6 28 52