Physics Questions

Two identical conductors of copper and aluminium are placed in an identical electric field The magnitude of induced charge in the aluminium will be O Zero Greater than in copper Equal to that in copper Less than in copper

surface in terms of interfacial tensions OR Account for the angle of contact in terms of interfacial tensions OR Draw diagram showing force due to surface ten sion at the liquid solid air solid air liquid inter face in case of i a drop of mercury on a plane solid surface and ii a drop of water on a plane Discuss the variation of angle of

The purpose of glass cover on top of a box type solar cooker is to A Allow one to see the food being cooked 3 Allow more sunlight into box C Prevent dust from entering box O Reduce heat loss by radiation

For a dipole having magnitude of charge q 4 10 6 C and distance between the charges d 0 02 m If this dipole is placed in a electric field E 2 x 105 N C Then maximum torque on the dipole will be 1 6 x 10 Nm 3 2 x 10 2 Nm 2 4 x 10 2 Nm hr mir 4 8 x 10 2 Nm

57 The shape of impure water meniscus is concave whereas that of mercury meniscus is convex Explain why OR Explain why the angle of contact of mercury with glass is obtuse while that of water with glass is acute 3 marks

wo very small spheres having charge Q and Q face each other at a certain distance between them If a dielectric having dielectric constant Kinserted between them then electrostatic force between them Increase Decrease Remains same Becomes zero The displacement of charge 2 C in the electric field E 21 3j k N C is 7 1 1 2k m The work done is 2 J 6 J 8 J 4 J

The ratio of electric potential due to a short electric dipole at point A whose position vector w r t centre of dipole makes 60 angle with direction of dipole moment to that at point B on axial position is Both points are at same distance from the center of the dipole 1 3 1 1 1 2

55 Explain why the free surface of some liquids in contact with a solid is not horizontal OR Explain the formation of concave and covex sur face of a liquid on the basis of molecular theory 3 marks

35 180 Mark for Review The displacement of charge 2 C in the electric field E 21 3 k N C is r 2k m The work done is 2 J 6 J 02 35 hr mi 8 J

30 180 7 2 J Two positive point charges of 10 C and 4 C are 10 cm apart The work in bringing them 5 cm closer is 2 4 J 4 8 J Mark for Review 3 6 J 02 3 hr m

50 180 An electron of mass m and charge e accelerated from rest through a potential difference Vin vacuum The final speed of electron will be m lev m 2e V m Mark for Review 2e V m

at a certain distance from a point charge in C he electric field is 200 V m and the potential is 300 V What is this distance 8 m 4 m 2 m 16 m The electric field just outside a spherical she of radius R having charge density will be G b w 20 0 a 280 40

e angle between the dipole moment and ctric field at any point on the equatorial point 90 45 0 180 The potential on the surface of hollow spher radius 2 m is 200 volt The potential at 1 m f the centre of the sphere is 100 volt 200 volt 400 volt Zero

Eight charged water drops each with a radius of 10 mm and a charge of 10 pico Coulomb merge into a single drop The potential of this single drop is 3 6 V 45 V 36 V 4 5 V

Equipotential surfaces associated with an electric field which is along y direction are Planes parallel to xz plane Planes parallel to xy plane Planes parallel to yz plane Coaxial cylinders of increasing radii along the y axis

180 Proton Which of the following is not deflected by electric field Electron Mark for Review a particle Neutron hr

e magnitude of electric force experienced by harged particle in an electric field depends Charge of the particle Velocity of the particle Direction of electric field Mass of the particle A soap bubble is given a positive charge then its radius Decreases Increases Remains unchanged Nothing can be predicted as information is insufficient

41 180 Mark for Review The value of electric permittivity of free space is 9 x 10 NC m 8 85 x 10 12 C2 Nm 8 85 x 10 12 Nm C 02 34 hr mi 9 x 109 C Nm

electron and proton are in uniform electric Id the ratio of their respective acceleration I be Zero Unity The ratio of the masses of proton and electron The ratio of the masses of electron and proton Point charges 9 4 C and 9 2 C are at point x 0 and x 4 respectively electri potential will be zero at points where x is cm X X 8 4 cm and x 8 cm cm and x 6 cm x 2 cm and x 6 cm x 1 cm and x 5 cm

If electric field is zero at a certain point then potential should be zero at that point If electric field is not zero at a certain point then potential should not be zero at that point If potential is zero at a certain point then electric field should be zero at that point If potential is zero at a certain point then electric field at that point may or may not be zero

hen one proton is taken towards the other oton then electric potential energy of the stem Decrease Increase Remains unchanged Becomes zero The points having equal potential are D q A B B and C B and D C and D

In an experiment a current carrying conductor is kept parallel to the magnetic needle on a compass If the direction of the current is from south to north then A North pole of the needle turns towards west B South pole turns toward west C Needle does not move D North pole turns towards east

wo small charged spheres separated by a listance dexert a force Fon each other If they re immersed in a liquid of dielectric constant 4 hen new force on any of the spheres will be distance between the charge remains same O 4F F FIN Three charges each of magnitude q are plac at the corner of an equilateral triangle of sic the electrostatic force on each charge will b q 4 a 39 4 a 2q 4 a q

The electrical potential at a point x y z is given by V x y xz 4 The electric field Eat that point is 2xy z i x 3xz k 2xy x y j 3xz y k z i xyzj 3 k 2xy z i xy j 3z xk

vo point charges 6 C and 16 C repel ch other with a force of 120 N If a charge of C is added to each of them then force tween them will becomes 40 N 30 N 20 N 60 N A ring of radius r has given a charge Q an uniformly distributed over its length If a c qis placed at the centre The electric pote energy of the charge q will be kqQ kqQ kq Q

Two equal point masses M are connected by a massless rigid rod of length 2A a dumbbell which is constrained to rotate about an axle fixed to the center of the rod at an angle Fig 1 134 The center of the rod is at the origin of coordinates the axle along the z axis and the dumbbell lies in the zz plane at t 0 The angular velocity w is a constant in time and is directed along the z axis a Calculate all elements of the inertia tensor Be sure to specify the coordinate system you use

What is the nature of the image obtained from surface of the spoor bulged outward and to what type mirror we can approximate it to A Inverted and concave mirror B Inverted and convex mirror C Erect and convex mirror Frect and e mirror

Consider the situation shown in fig The capacitor A has a charge q on it whereas B is uncharged The charge appear ing on the capacitor B a long time after the switch is closed is 9 H A B

The equivalent capacitance of three capacitors of capacitance C C and C connected in parallel is 12 units and the product C C C 48 When the capacitors C and C are connected in parallel the equivalent capacitance is 6 units Then the capacitance are 2 4 6 2 1 5 6 10 Vi 3 1 5 2 5 8 4 2 3 7 lied between A and B a charge of 0 75 mC is stored in the system of ca

An object of 5 cm in size is placed at a distance of 20 cm from concave mirror of focal length 15 cm what is the nature of the image A Real inverted enlarged B Real erect diminished C Virtual inverted diminished D Virtual erect diminished

charge Q is enclosed by a Gaussian spherical urface of radius R If charge and radius of aussian surface is doubled then outward ectric flux will Becomes four times Remains same Becomes doubled Becomes half The total electric flux through a cube when charge 4q is places at one corner of the cub 4q 80 q 480

If the charge on a body is increased by 2 C the energy stored in it increases by 21 The original charge on the in micro coulombs is 1 10 TI 2 20 3 30 4 40

A capacitor of capacity C 1 uF can withstand maximum voltage V 6 kV and other capacitor C 3 uF can with stand maximum voltage V 4 kV If these are connected in series then the combined system can withstand a maxi 2 mum voltage at 1 4 kV 2 6 kV 3 8 kV 4 10 kV Conducting sphere of radius R is covered by concentric sphere of radius R Capacity of this combination is propor

9 Take the mean distance of the moon and the sun earth to be 0 4 106 km and 150 106 km respectively Their masses are 8 102 kg and 2 1030 kg respectively The radius of the earth is 6400 km Let AF be the difference in the forces exerted by the moon at the nearest and farthest points on the earth and AF2 be the difference in the force exerted by the sun at the nearest and farthest points on the earth Then the number closest to is a 2 b 0 6 c 6 AF AF d 10

15 Two charges of 25 x 10 coulomb and 25 x 10 coulomb are placed 6 m apart Find the electric field intensity ratio at points 4 m from the centre of the electric dipole 1 on axial line ii on equatorial line 0 1000 49 49 500 49 49

M The energy stored in the capacitor is U when it is charged with a battery After disconnecting battery another capac tor of same capacity is connected in parallel with it then energy stored in each capacitor is 1 U ald 3 9U 4 8U

Capacity of a conductor depends upon 1 Size of conductor 3 Material of conductor 2 Thickness of conductor All of these ortional t

Two capacitors of capacitances 3uF and 6uF are charged to a potential of 12V each They are now connected to each other with the positive plate of each joined to the negative plate of the other The potential difference across each will be 1 6V 2 4V 3 3V 4 Zero The aquiplant capacitance between the points A and B is

An object is kept at infinite distance produces a bright and sharp image on the screen kept at a distance x in front of concave mirror then x is equal to A Radius of curvature B Twice of the focal length C Focal length of the mirror

Two capacitors of capacity C and C are charged upto a potential V and V then condition for not flowing the charg between on connected them in parallel 1 C C 2 C V C V 2 3 V V 2 C C 4 V V

The capacity of a parallel plate capacitor depends upon 1 Nature of the metal 2 Distance between the plates 3 Thickness of the plates 4 Potential difference between the plates

The equivalent capacitance of the circuit shown between points A and B HH 1 F 2 1 F 5 2 HF 1 F 1 F 2 F HH HF B 00 O 7 4 F

2 A bar of mass m is suspended horizontally on two vertical springs of spring constant k and 3k The bar bounces up and down while remaining horizontal Find the time period of oscillation of the bar neglect mass of springs and friction everywhere A 2n C m 2m 3k B D F Fixed pulley K

Three charges each of q are placed at the vertices of an equilateral triangle The charge needed at the centre of the triangle for the charges to be in equilibrium is A C 3q B 3 D

6 The equivalent capacitance in the circuit shown in figure will be 10 A 4uF 4 F B 4 F 3 6 F 4 F 4uF HH 4 8 F

Two capacitors are joined as shown in figure Potentials at points A and B are V and V respectively The potential of point D is 1 V V 2 A V HIC C V C V C C D 3 Hlc C V C V C C B 4 C V C V C C

6 F 2 12 F 3 18 F Ten capacitors are joined in parallel and charged with a battery up to a potential V They are then disconnected from battery and joined again in series then the potential of this combination will be 1 V 2 10 V 3 5 V 4 2 V What is the equivalent capacitance between A and B

The work done against electric forces in increasing the potential difference of a condenser from 20V to 40V is W The work done in increasing its potential difference from 40V to 50V will be 1 4W 2 3 W 4 3 2W 4 W 2

The work done in doubling the separation between plates of a parallel plate capacitor of capacity C and having charge Qis 12 1 Q 4 20 2C 4C ograph of fnl against t in a charging R C circuit If the resistance of the circuit is doubled which 2 3

58 The alkane that gives only one mono chloro product on chlorination with Cl in presence of diffused sunlight is 1 2 2 dimethylbutane 3 n pentaneb 2 neopentane 4 Isopentane