Physics-
General
Easy
Question
Battery shown in figure has e.m.f. E and internal resistance r. Current in the circuit can be varied by sliding the contact J. If at any instant current flowing through the circuit is I, potential difference between terminals of the cell is V, thermal power generated in the cell is equal to h fraction of total electrical power generated in it.; then which of the following graph is correct
- Both (a) and (b) are correct
The correct answer is: Both (a) and (b) are correct
Terminal voltage 
Hence the graph between V and i will be a straight line having negative slope and positive intercept.
Thermal power generated in the external circuit
Hence graph between P and I will be a parabola passing through origin.
Also at an instant, thermal power generated in the cell = 
and total electrical power generated in the cell = Ei. Hence the fraction 
so 
. It means graph between h and I will be a straight line passing through origin.
Related Questions to study
Physics-
In a copper voltameter, mass deposited in 6 minutes is m gram. If the current-time graph for the voltameter is as shown here, then the E.C.E of the copper is
In a copper voltameter, mass deposited in 6 minutes is m gram. If the current-time graph for the voltameter is as shown here, then the E.C.E of the copper is
Physics-General
Physics-
A constant current i is passed through a resistor. Taking the temperature coefficient of resistance into account, indicate which of the plots shown in figure best represents the rate of production of thermal energy in the resistor
A constant current i is passed through a resistor. Taking the temperature coefficient of resistance into account, indicate which of the plots shown in figure best represents the rate of production of thermal energy in the resistor
Physics-General
Physics-
A metal rod of length 2m has cross sectional areas 2A and A as shown in figure. The ends are maintained at temperatures 100°C and 70°C. The temperature at middle point C is
A metal rod of length 2m has cross sectional areas 2A and A as shown in figure. The ends are maintained at temperatures 100°C and 70°C. The temperature at middle point C is
Physics-General
Physics-
Two metal cubes 
and 
of same size are arranged as shown in the figure. The extreme ends of the combination are maintained at the indicated temperatures. The arrangement is thermally insulated. The coefficients of thermal conductivity of and are 
and 
, respectively. After steady state is reached, the temperature of the interface will be
Two metal cubes and of same size are arranged as shown in the figure. The extreme ends of the combination are maintained at the indicated temperatures. The arrangement is thermally insulated. The coefficients of thermal conductivity of and are and , respectively. After steady state is reached, the temperature of the interface will be
Physics-General
Physics-
The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar shown in the figure. What will be the temperature at the junction of copper and steel
The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar shown in the figure. What will be the temperature at the junction of copper and steel
Physics-General
Physics-
Two bars of thermal conductivities K and 3K and lengths 
and 
respectively have equal cross-sectional area, they are joined lengths wise as shown in the figure. If the temperature at the ends of this composite bar is 
and 
respectively (see figure), then the temperature 
of the interface is
Two bars of thermal conductivities K and 3K and lengths and respectively have equal cross-sectional area, they are joined lengths wise as shown in the figure. If the temperature at the ends of this composite bar is and respectively (see figure), then the temperature of the interface is
Physics-General
Physics-
If two metallic plates of equal thicknesses and thermal conductivities 
and 
are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be
If two metallic plates of equal thicknesses and thermal conductivities and are put together face to face and a common plate is constructed, then the equivalent thermal conductivity of this plate will be
Physics-General
Physics-
Two identical square rods of metal are welded end to end as shown in figure (i), 20 calories of heat flows through it in 4 minutes. If the rods are welded as shown in figure (ii), the same amount of heat will flow through the rods in
Two identical square rods of metal are welded end to end as shown in figure (i), 20 calories of heat flows through it in 4 minutes. If the rods are welded as shown in figure (ii), the same amount of heat will flow through the rods in
Physics-General
Physics-
In the P-V diagram shown in figure ABC is a semicircle. The work done in the process ABC is
In the P-V diagram shown in figure ABC is a semicircle. The work done in the process ABC is
Physics-General
Physics-
Volume versus temperature graph of two moles of helium gas is as shown in figure. The ratio of heat absorbed and the work done by the gas in process 1-2 is
Volume versus temperature graph of two moles of helium gas is as shown in figure. The ratio of heat absorbed and the work done by the gas in process 1-2 is
Physics-General
Physics-
The V-i graphs A and B drawn for two voltameters. Identify each graph
The V-i graphs A and B drawn for two voltameters. Identify each graph
Physics-General
Physics-
Which of the following plots may represent the thermal energy produced in a resistor in a given time as a function of the electric current
Which of the following plots may represent the thermal energy produced in a resistor in a given time as a function of the electric current
Physics-General
Physics-
In a copper voltameter, mass deposited in 30 second is m gm. If the time-current graph is as shown in figure, ECE of copper is
In a copper voltameter, mass deposited in 30 second is m gm. If the time-current graph is as shown in figure, ECE of copper is
Physics-General
Physics-
For ensuring dissipation of same energy in all three resistors 
connected as shown in figure, their values must be related as
For ensuring dissipation of same energy in all three resistors connected as shown in figure, their values must be related as
Physics-General
Physics-
In the following circuit, 5 W resistor develops 45 J/s due to current flowing through it. The power developed per second across 12 W resistor is
In the following circuit, 5 W resistor develops 45 J/s due to current flowing through it. The power developed per second across 12 W resistor is
Physics-General
