List of top Physics Questions on Heat Transfer asked in AP EAMCET

Water of mass \( m \) at \( 30^\circ C \) is mixed with \( 5 \) g of ice at \( -20^\circ C \). If the resultant temperature of the mixture is \( 6^\circ C \), then the value of \( m \) is: (Given: Specific heat capacity of ice = \( 0.5 \) cal \( g^{-1} \) \( ^\circ C^{-1} \), Specific heat capacity of water = \( 1 \) cal \( g^{-1} \) \( ^\circ C^{-1} \), Latent heat of fusion of ice = \( 80 \) cal \( g^{-1} \))
A metal ball of mass 100 g at \( 20^\circ C \) is dropped in 200 ml of water at \( 80^\circ C \). If the resultant temperature is \( 70^\circ C \), then the ratio of specific heat of the metal to that of water is:
A sphere of surface area \(4\ \text{m}^2\) at temperature \(400\ \text{K}\) and having emissivity \(0.5\) is located in an environment of temperature \(200\ \text{K}\). The net rate of energy exchange of the sphere is
\[ \text{Stefan Boltzmann constant } \sigma=5.67\times10^{-8}\ \text{W m}^{-2}\text{K}^{-4} \]