Science (English Medium) Class 12 - CBSE Question Bank Solutions

A point charge Q is placed at the origin. Find the electrostatic energy stored outside the sphere of radius R centred at the origin.

A metal sphere of radius R is charged to a potential V.

1. Find the electrostatic energy stored in the electric field within a concentric sphere of radius 2 R.
2. Show that the electrostatic field energy stored outside the sphere of radius 2 R equals that stored within it.

A large conducting plane has a surface charge density `1.0 xx 10^-4  "Cm"^-2` . Find the electrostatic energy stored in a cubical volume of edge 1⋅0 cm in front of the plane.

Figure shows two identical parallel plate capacitors connected to a battery through a switch S. Initially, the switch is closed so that the capacitors are completely charged. The switch is now opened and the free space between the plates of the capacitors is filled with a dielectric of dielectric constant 3. Find the ratio of the initial total energy stored in the capacitors to the final total energy stored.

Obtain the expression for the energy stored in a capacitor connected across a dc battery.

Do free electrons travel to region of higher potential or lower potential?

Prove that, if an insulated, uncharged conductor is placed near a charged conductor and no other conductors are present, the uncharged body must be intermediate in potential between that of the charged body and that of infinity.

A parallel plate capacitor (A) of capacitance C is charged by a battery to voltage V. The battery is disconnected and an uncharged capacitor (B) of capacitance 2C is connected across A. Find the ratio of total electrostatic energy stored in A and B finally and that stored in A initially.

Explain the hegemony of the United States of America as structural power.

'Resistance is the only option available to overcome the hegemony". Justify the statement by comparing it to other antihegemony strategies.

Write the four forms of power which reflect the U. S. Hegemony.

The rivalry between USA & USSR during the post-second world war period is known as ____________.

Which of the following statements about the NIEO is false?

The fall of the ____________ symbolizes the end of the Cold War.

The high point of Cold War was ______

Why didn't war happen during the Cold War?

Assertion: The Cold War was neither war nor an armed military conflict nor a condition of peace. It was rather a state of uneasy peace.

Reason: The Cold War was not being fought by clever moves, propagandist activities, and diplomatic conflicts.

Assertion: International Organisations play a very important role in maintaining peace.

Reason: Countries have conflicts and differences with each other.

In which of the following matters does International Organisation help?

1. To establish better living conditions in democratic countries.
2. In matters of peace & war.
3. To prevent violations of human rights.
4. To resolve territorial disputes.

The re-organization of the states on the basis of language had a negative effect ______