Question

Bell metal is an alloy of:
(A) copper and tin $ \left( {{\text{1:4}}} \right) $
(B) copper and zinc $ \left( {{\text{4:1}}} \right) $
(C) copper and tin $ \left( {{\text{4:1}}} \right) $
(D) copper and iron $ \left( {{\text{4:1}}} \right) $

Answer 1

Hint: In the above question, it is asked about the composition of bell metal. Bell metal is a hard alloy which is used for making bells and related instruments. It should have less ductility and more resonance of sound. It is a form of bronze.

Complete step by step solution
We know that bell metal is used for making bells and related instruments. It is a form of bronze with higher tin content. Usually, approximate $ {\text{78% }} $ copper and $ {\text{22% }} $ tin by mass.
The higher tin content increases rigidity of the metal and also it increases the resonance. It is used in industries in the form of piston rings, bearings, bushings.
Tin and copper are relatively soft metals that deform on striking but alloying them makes a metal which is harder and less ductile. The elasticity of bell metals is more than elasticity of either of the metals. This metal combination produces a tough, long-wearing material that is resistant to oxidation and subject only to an initial surface weathering.
The ratio of copper and tin is approximately $ {\text{4:1}} $ .
So, the correct option is option-C.

Note
-Increasing the tin content increases the decay time of the bell strike and hence makes the bell more sonorous.
-In Russia, church bells are commonly cast with a unique mixture of copper and tin, often the silver is added, to produce their unique sonority and resonance.
-Bell Bronze is the purest type of bronze in the bronze family. Not only is the copper content higher than traditional bronze itself (traditional bronze is 80% copper, 20% tin), there is no contamination from other metals in the alloy. This is the reason that a bronze bell gives you such perfect tone and clarity.