Recent questions and answers in Class12

The disintegration rate of a radioactive sample at a certain instant is 4750 dpm . Five minute later rate becomes 2700 disintegration per minute . Then the decay constant is

answered Feb 10, 2020 by ayomidevictoria002

2 answers

Electromagnetic waves are transverse in nature is evident by

answered Jan 30, 2020 by mohthapa

2 answers

A negatively and uniformly charged disk is rotating in a clockwise direction as viewed from above. The direction of magnetic field at a point A is

answered Sep 20, 2019 by prasoonverma514551

1 answer

If level of modulation is increased ________ power is increased

answered Jul 4, 2019 by snehalligade207

2 answers

The main purpose of modulation is to

answered Nov 2, 2018 by chetanwane

2 answers

The capacitance of parallel plate capacitor does not depend upon

answered Oct 21, 2018 by balu.rathod7585

3 answers

Three capacitors, each of capacitance C are connected to a battery of voltage V. When key K is closed, the charge which will flow through the battery is (see figure).

answered Oct 16, 2018 by nitishnetha

1 answer

A metallic resistor is connected across a battery. If the number of collisions of free electrons with the lattice is somehow decreased in the resistor, the current will

answered Jul 18, 2018 by ashishkhatua444

2 answers

As the temperature of a metallic conductor is increased, the product of resistivity and conductivity

answered Jul 4, 2018 by upretipramod44

2 answers

A particle is projected perpendicular to a uniform magnetic field. The area bounded by the trajectory of the particle is directly proportional to

answered Jun 2, 2018 by kasirnazir620

2 answers

A person looks in to a spherical mirror . The size of image of his face is twice the actual size of his face. If the face is at distance 20 cm then find the radius of curvature of mirror.

answered Dec 1, 2017 by br.singh21914

2 answers

Minimum size of plane mirror, required to see full image of an observer is :

answered Jun 20, 2017 by parthgite94

2 answers

Two identical particles , each having a charge of $\;2\times10^{-4}\;C\;$ and mass 10g are kept at a separation of 10 cm and released . What would be the speeds of the particles when the separation becomes large ?

answered Apr 19, 2017 by mahajanmridul1997

2 answers

electric charge Q,Q and -2Q resp. are placed at the three corners of an equilateral triangle of side a . magnitude of the elctrical dipole moment of the system is

answered Mar 23, 2017 by abdulsalamottathil

2 answers

Two identical charged spheres are suspended by strings of equal length . The strings make an angle of $\;60^{0}\;$ with each other . When suspended in a liquid of density $\;0.5 g/cc,\;$ the angle remains the same . The dielectric constant of the liquid is [density of material of sphere is $\;1.5 g/cc\;$]

answered Jun 24, 2016 by dongrearchit

2 answers

Six charges are placed at the vertices of a rectangular hexagon as shown in fig. The electric field on the line passing through point O and perpendicular to the plane of the figure as a function of X from point O is (x>>>a)

answered Aug 2, 2015 by pady_1

1 answer

a body dropped freely from a height h on to a horizontal plane, bounces up and down and finally comes to rest. the coefficient of restitution is e. the ratio of velocities at the beginning and after two rebounds is

answered Jul 29, 2015 by vijayalakshmi.r

1 answer

force of interaction between two axial short electric dipoles whose centres are R distance apart varies as

answered May 12, 2015 by sharmaaparna1

1 answer

Coolant in radiations automobile must be

answered Feb 16, 2015 by micheal.powers

2 answers

Which of the following can be used to determine the velocity of sound in solids and gases

answered Dec 23, 2014 by christian.miles

2 answers

find out the value of d as shown in fig.

answered Dec 13, 2014 by vijayalakshmi.r

1 answer