Question:

Which of the following material cannot be machined using ECM?

A.

high strength alloys

B.

hardened steels

C.

nonconductive materials

D.

all of the mentioned

Answer» c. nonconductive materials

Question:

Local metal removal rates are high at which gap locations mentioned below?

A.

small gap

B.

medium gap

C.

large gap

D.

none of the mentioned

Answer» a. small gap

Question:

At constant gap thickness material removal becomes equal to feed rate. What is this gap called?

A.

equal gap

B.

equilibrium gap

C.

unique gap

D.

narrow gap

Answer» b. equilibrium gap

Question:

Electro chemical dissolution phase starts with the movement of ions between which two components?

A.

cathode and anode

B.

cathode and power source

C.

power source and anode

D.

power source and electrolyte

Answer» a. cathode and anode

Question:

In the following ratios of metal dissolved amounts, which one represent the current efficiency?

A.

observed to theoretical

B.

theoretical to observed

C.

all of the mentioned

D.

none of the mentioned

Answer» a. observed to theoretical

Question:

Machining conditions leading to high accuracy are associated with                  surface roughness and                  productivity.

A.

greater, greater

B.

smaller, greater

C.

greater, smaller

D.

smaller, smaller

Answer» b. smaller, greater

Question:

At constant feed rates what happens to gap thickness?

A.

increases

B.

decreases

C.

becomes constant

D.

none of the mentioned

Answer» c. becomes constant

Question:

When the electrolyte flow is low, what happens to the current efficiency?

A.

increases

B.

decreases

C.

remains same

D.

increase and then decrease

Answer» b. decreases

Question:

Too small gap causes which of the following effects?

A.

sparking

B.

short circuit

C.

sparking & short circuit

D.

none of the mentioned

Answer» c. sparking & short circuit

Question:

Which type of damage is caused by deterioration which is caused by spark?

A.

reparable

B.

irreparable

C.

all of the mentioned

D.

none of the mentioned

Answer» b. irreparable