Question

Assertion (A): In Electrical Discharge Machining (EDM), fragile parts can be machined without distortion because no mechanical work is involved.
Reason (R): The surface finish of the finished components made using EDM is poor because of presence of small craters.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

EDM → No cutting force but thermal damage leads to poor surface finish.

Answer 1

The Correct Option is B

Concept: Electrical Discharge Machining (EDM) is a non-traditional machining process where material removal occurs due to electrical sparks instead of mechanical cutting forces.

Step 1: Analyze Assertion (A).
In EDM:
• No physical contact between tool and workpiece
• Material removal occurs due to thermal energy of sparks
• No cutting forces are involved Thus:
• No mechanical stresses are induced
• Fragile or delicate components can be machined without deformation Hence Assertion (A) is correct.

Step 2: Analyze Reason (R).
EDM process produces:
• Localized melting and vaporization
• Formation of tiny craters on surface Thus:
• Surface finish is comparatively rough
• Presence of craters reduces smoothness Hence Reason (R) is also correct.

Step 3: Check logical relation.
Assertion is about absence of mechanical forces.
Reason is about surface finish characteristics. These two are independent facts. Final Answer: \[ \boxed{\text{Both (A) and (R) are correct but (R) is not the correct explanation of (A)}} \]