The source of sun's energy is a reservoir of coal burning in its core. Is this statement true?

An electromagnet is a solenoid with a soft iron core. Is this statement true.

What are the sources of energy in sun and stars?

The resistivity of a substance depends on its length and area of cross section. Is the statement true or false.

These questions consist of two statement each, printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses. A. If both Assertion and Reason are true and Reason is a correct explanation of the Assertion. B. If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion. C. If Assertion is true but Reason is false. D. If both Assertion and Reason are false. Assertion: The quiescent centre acts as a reservoir of relatively resistant cells which consitute a permanent source of active initials. Reason. The cells of the inactive region of quiescent centre become active when the previous active initials get damaged.

Solar Constant (s) : s =((r )/(R ))^(2)sigmaT^(4) , where r= radius of sun ,R= distance of the earth from the centre of sum , T= absolute temperature of sun . Value of solar constant is 1.937 "cal cm"^(-2) "min"^(-1) . Is the statement true?

Most of the sources of energy we use represent stored solar energy which of the following is not ultimately derived from the sun's energy?

In the following statements ,tick 'T' against those which are true and 'F' against those which are false. The number opf oscillations per second of a viberating object is called its time period. (T/F)