Question

An iron cylinder contains helium at a pressure of 250 $kPa$ and ${27}^{\circ }C$. The cylinder can withstand a pressure of $1\times {10}^5$ $Pa$. The room in which cylinder is placed catches fire. Will cylinder blow up before it melts or not? [melting point of cylinder = 1800 $K$]

• A. Yes
• B. No
• C. Can't predict
• D. None of these

Answer 1

The correct option is A Yes

Initial temperature $T={27}^{o}C=300K$
Final temperature $T^{\prime }=1800K$
Initial pressure $P=250kPa=2.5\times {10}^{5}Pa$
The pressure is directly proportional to temperature
$P^{\prime }=P\times \frac{T^{\prime }}{T}=2.5\times {10}^5\times \frac{1800}{300}=1.5\times {10}^{6}Pa$
But the cylinder can withstand a pressure of $1\times {10}^{5}Pa$ only. Since, the pressure at melting point is higher than the pressure which the cylinder can withstand, the cylinder will below up before it melts.