Sometimes it is said that "heat is developed" in a resistance when there is an electric eurrent in it .Recall that heat is defined as the energy being transferred due to the temperature difference, Is the statement under quotes technically correct?

Give mode of heat transfer due to temperature difference.

Assertion : Work and heat are two equivalent form of energy Reason: Work is the transfer of mechanical energy irrespective of temperature difference, whereas heat is the transfer of thermal energy because of temperature difference only.

An electric heater is used in a room of total wall area 137m^(2) to maintain a temperature of +20^(@)C inside it when the outside temperature is -10^(@)C . The walls have three different layers materials . The innermost layer is of wood of thickness 2.5 cm, in the middle layer is od cement of thickness 1.0 cm and the outermost layer is of brick of thickness 25.0 cm. find the power of the electric heater. Assume that there is no heat loss through the floor and the ceiling. The thermal conductives of wood, cement and brick are 0.125, 1.5 and 1.0 watt//m// .^(@)C respectively.

The ends of a long bar are maintained at different temperatures and there is no loss of heat from the sides of the bar due to conduction or radiation. The graph of temperature against distance of the bar when it has attained steady state is shown here. The graph shows ltimg src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/ALN_PHY_R03_E09_009_Q01.png" width="80%"gt (i) the temperature gradient is not uniform. (ii) the bar has uniform cross-sectional area. (iii) the cross-sectional area of the bar increases as the distance from the hot end increases. (iv) the cross-sectional area of the bar decreases as the distance from the hot end increases

Figure shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B =0.50 T, resistance of the closed loop containing the rod 9.0 m Omega . Assume the field to be uniform. (a) Suppose K is open and the rod is moved with a speed of 12 "cm s"^(-1) in the direction shown. Give the polarity and magnitude of the induced emf. (b) Is there an excess charge built up at the ends of the rods when K is open ? What if K is closed ? (c) With K open and the rod moving uniformly, there is no net force on the electrons in the rod PQ even though they do experience magnetic force due to the motion of the rod. Explain. (d) What is the retarding force on the rod when K is closed ? How much power is required (by an external agent) to keep the rod moving at the same speed (= 12 cm s^(-1) ) when K is closed ? How much power is required when K is open? (f)How much power is dissipated as heat in the closed circuit ? What is the source of this power ? (g) What is the induced emf in the moving rod if the magnetic field is parallel to the rails instead of being perpendicular ?

When current passes through resistor due to its resistive property heat is produced. Error in measurement of resistance, current and time is 1%, 2% and 1% respectively, then what will be percentage error in measurement of heat energy ?

An electric toaster uses nichrome for its heating element. When a negligibly small current passes through it, its resistance at room temperature (27.0^(@)C) is found to be 75.3 Omega . When the toaster is connected to a 230 V supply, the current settles, after a few seconds, to a steady value of 2.68 A. What is the steady temperature of the nichrome element ? The temperature coefficient of resistance of nichrome averaged over the temperature range involved , is 1.70 xx 10^(-4) ""^(@) C^(-1) .

An electric toaster uses nichrome for its heating element. When a negllgibly small current pases through it, its resistance at room temperature (27.0^(@)C) is found to be 75.3 Omega. When the toaster is connected to a 230 V supply, the current settles, after a few seconds, to a steady value of 2.68A. What is the steady temperature of the nichrome element ? The temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 xx 10 ^(-4)"" ^(@)C ^(-1).

Consider a hypothetical situation where we are comparing the properties of two crystals made of atom A and atom B . Potential energy (U) v//s interatomic separation (r) graph for atom A and atom B is shown in figure (i) and (ii) and respectively. When we heat the crystal of either atoms ,the atom undergo oscillation. Choose correct statement for atoms of crystal A

An electric iron consumes energy at a rate of 840 W, when heating is at the maximum rate and 360 W, when heating is atthe minimum. The voltage is 220V. What are the current and the resistance in each case?