Four identical spheres, each of mass 1 kg and radius 10 cm, are placed on a horizontal surface touching one another such that their centres are located at the corners of a square of side 20 cm. What is the distance of the centre of mass from the centre of sphere?

Directions: The following question has four choices out of which ONLY ONE is correct.

Seven conductors each of resistance R are arranged as shown in the figure. (i), fig. (ii) and fig. (iii). If R1, R2and R3are the respective equivalent resistances between A and B, then

Directions:The following question has four choices out of which ONLY ONEis correct.

Following question contains statements given in two columns, which have to be matched. The statements in Column I are labeled A, B, C and D, while the statements in Column II are labeled p, q, r, s and t. Any given statement in Column I can match with ONE OR MORE statements (s) in column II. The appropriate bubbles corresponding to the answers to these questions have to be darkened as illustrated in the following example:

If the correct matches are A - p, s and t; B - q and r, C - p and q; and D - s and t: the correct darkening of bubbles will look the following.

When a system is taken from state i to state f along the path iaf, it is found that Q = 50 cal and W = 20 cal . Along the path ibf Q = 36 cal. W along the path ibf is:

Directions:For the given statements of Assertion and Reason, mark the correct answer as:

(a) if both assertion and reason are true and reason is the correct explanation of assertion

(b) if both assertion and reason are true, but reason is not the correct explanation of assertion

(c) if assertion is true, but reason is false

(d) if both assertion and reason are false

Assertion:Reversible systems are difficult to find in real world.

Reason:Most processes are dissipative in nature.

The pressure and density of a diatomic gas  change adiabatically from  to. If, then what should be the value of ?

Starting with the same initial conditions, an ideal gas expands from volume V1to V2 in three different ways. The work done by the gas is W1if the process is purely isothermal; W2, if purely isobaric, and W3,if purely adiabatic. Then:

An engine has an efficiency of 1/6 When the temperature of the sink is reduced by 62^°C, its efficiency is doubled. The temperature of the source is

A wire is cut into four pieces, which are put together by sides to obtain one conductor. If the original resistance of wire was R, then the resistance of the bundle will be

If VB- VD= 0 in the given circuit, then what is the value of R?