A lead bullet penetrates into a solid object and melts. Assuming that 40% of its kinetic energy is used to heat it, the initial speed of bullet is: ( given initial temperature of the bullet = 127°C,melting point of the bullet = 327°C. latent heat of fusion of lead = $2 .5 \times 10^{4} {JKg}^{- 1}$ , specific heat capacity of lead = $125 J / KgK$ )

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!

An Intiative by Sri Chaitanya

$500 {ms}^{- 1}$

$125 {ms}^{- 1}$

$250 {ms}^{- 1}$

$600 {ms}^{- 1}$

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

$\begin{array}{l} 40 % of K . E = msΔT + {mL}_{f} \\ \Rightarrow \frac{40}{100} \times 1 / 2 {mV}^{2} = ms (327 - 127) + {mL}_{f} \\ \Rightarrow \frac{20}{100} \times V^{2} = 200 S + L_{f} \\ \Rightarrow \frac{1}{5} V^{2} = 200 \times 125 \times 2 .5 \times 10^{4} \\ \Rightarrow V^{2} = 1000 \times 125 \times 2 .5 \times 10^{4} \times 5 \\ \Rightarrow V^{2} = 250000 \\ \Rightarrow V = 500 m / s \end{array}$

Watch 3-min video & get full concept clarity

tricks from toppers of Infinity Learn

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

🔥 Start Your JEE/NEET Prep at Just ₹1999 / month - Limited Offer! Check Now!

Get Expert Academic Guidance – Connect with a Counselor Today!

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET