Question 37

The Correct Answer is B **Explanation for Option B (4 being the Piston):** The label '4' in a typical diagram of an internal combustion engine points to the component that slides up and down within the cylinder (indicated by label 3). This component is the **piston**. The piston's function is to transmit force from the expanding gases in the combustion chamber to the crankshaft via the connecting rod (label 7), and also to compress the intake air (in a diesel engine). **Explanation for Incorrect Options:** * **A) 3:** Label '3' typically points to the **cylinder** (or cylinder liner), which is the stationary outer housing within which the piston moves. * **C) 7:** Label '7' points to the **connecting rod**, the linkage that connects the piston (4) to the crankshaft (10). * **D) 10:** Label '10' points to the **crankshaft**, the main rotating component that converts the reciprocating motion of the piston into rotary motion.