Question

calories $1$ =
(A) $4180\text{ J}$
(B) $4.18\text{ J}$
(C) $11.418\text{ J}$
(D) None of these

Answer 1

Hint Energy is the ability to do work. It is measured in joule or calories. . Calorie is the cgs unit of energy and joule is the S.I unit of energy.
To convert a CGS formula to S.I , multiply the symbols by a corresponding factor which is a standard formula and by this , the solution can be calculated.

Complete Step by step solution
$1$ calorie is equal to $4.18\text{ J}$
Joule is the S.I. unit of energy.
Energy is often expressed as a “calorie”, which is the amount of heat needed to raise the temperature of one gram of water by one degree Celsius.
$1$ kilocalorie is equal to $4148\text{ J}$.

[option B].

Additional information
In the nutritional context, the kilojoule is the S.I. unit of food energy. The word calorie is commonly used with the number of kilocalories (kcal) of nutritional energy measured.
Two main definitions of calorie are used:
Small calorie or gram calorie: It is the amount of heat energy needed to raise the temperature of one gram of water by one degree Celsius.
Large calorie or kilocalorie: it is the amount of heat needed to raise the temperature of one kilogram of water by one degree celsius.
Thus,
$1\text{ kilocalorie }\left( kcal \right)=1000\text{ calories}\left( cal \right)$

Note Knowledge of concepts of energy and its units (CGS or SI units) is required.