Physics-
General
Easy
Question
Two conducting rods A and B of same length and cross-sectional area are connected (i) In series (ii) In parallel as shown. In both combination a temperature difference of 100°C is maintained. If thermal conductivity of A is 3K and that of B is K then the ratio of heat current flowing in parallel combination to that flowing in series combination is
The correct answer is:
Heat current 
Þ 
In first case : 
In second case :
\ 
Related Questions to study
physics-
The following figure shows two air-filled bulbs connected by a U-tube partly filled with alcohol. What happens to the levels of alcohol in the limbs X and Y when an electric bulb placed midway between the bulbs is lighted
The following figure shows two air-filled bulbs connected by a U-tube partly filled with alcohol. What happens to the levels of alcohol in the limbs X and Y when an electric bulb placed midway between the bulbs is lighted
physics-General
physics-
The top of insulated cylindrical container is covered by a disc having emissivity 0.6 and thickness 1 cm. The temperature is maintained by circulating oil as shown in figure. If temperature of upper surface of disc is 127°C and temperature of surrounding is 27°C, then the radiation loss to the surroundings will be (Take 
The top of insulated cylindrical container is covered by a disc having emissivity 0.6 and thickness 1 cm. The temperature is maintained by circulating oil as shown in figure. If temperature of upper surface of disc is 127°C and temperature of surrounding is 27°C, then the radiation loss to the surroundings will be (Take
physics-General
physics-
In the following figure, two insulating sheets with thermal resistances R and 3R as shown in figure. The temperature q is
In the following figure, two insulating sheets with thermal resistances R and 3R as shown in figure. The temperature q is
physics-General
physics-
Five identical rods are joined as shown in figure. Point A and C are maintained at temperature 120°C and 20°C respectively. The temperature of junction B will be
Five identical rods are joined as shown in figure. Point A and C are maintained at temperature 120°C and 20°C respectively. The temperature of junction B will be
physics-General
physics-
Two friends A and B are waiting for another friend for tea. A took the tea in a cup and mixed the cold milk and then waits. B took the tea in the cup and then mixed the cold milk when the friend comes. Then the tea will be hotter in the cup of
Two friends A and B are waiting for another friend for tea. A took the tea in a cup and mixed the cold milk and then waits. B took the tea in the cup and then mixed the cold milk when the friend comes. Then the tea will be hotter in the cup of
physics-General
physics-
A Copper plate is soldered between two steel plates . All the plates have the same cross- section (A) and length l. The coefficient of thermal expansions are 
and their young’s moduli are 
respectively. What force will arise in the plates if the temperature is increased by 
? (Assume that the plates suffer the same net expansion)
A Copper plate is soldered between two steel plates . All the plates have the same cross- section (A) and length l. The coefficient of thermal expansions are and their young’s moduli are respectively. What force will arise in the plates if the temperature is increased by ? (Assume that the plates suffer the same net expansion)
physics-General
physics-
Heat is extracted from a 1 kg substance at a constant rate of 2 kJ/ hour. Temperature vs-Time graph is plotted. The latent heat of substance is
Heat is extracted from a 1 kg substance at a constant rate of 2 kJ/ hour. Temperature vs-Time graph is plotted. The latent heat of substance is
physics-General
physics-
A block of steel heated to 
is left in a room to cool. Which of the curves shown in figure represents the correct cooling behaviour?
A block of steel heated to is left in a room to cool. Which of the curves shown in figure represents the correct cooling behaviour?
physics-General
physics-
The energy distribution 
with the wavelength 
for the black body radiation at temperature 
is shown in the figure. As the temperature is increased the maxima will
The energy distribution with the wavelength for the black body radiation at temperature is shown in the figure. As the temperature is increased the maxima will
physics-General
physics-
Shown below are the black body radiation curves at temperatures T1 and T2 (T2>T1) . Which of the following plots is correct
Shown below are the black body radiation curves at temperatures T1 and T2 (T2>T1) . Which of the following plots is correct
physics-General
physics-
A body cools in a surrounding which is at a constant temperature of 
. Assume that it obeys Newton's law of cooling. Its temperature 
is plotted against time t. Tangents are drawn to the curve at the points 
and 
. These tangents meet the time axis at angles of 
and 
, as shown
A body cools in a surrounding which is at a constant temperature of . Assume that it obeys Newton's law of cooling. Its temperature is plotted against time t. Tangents are drawn to the curve at the points and . These tangents meet the time axis at angles of and , as shown
physics-General
physics-
Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match
Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match
physics-General
physics-
The adjoining diagram shows the spectral energy density distribution 
of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature T is
The adjoining diagram shows the spectral energy density distribution of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature T is
physics-General
physics-
The plots of intensity versus wavelength for three black bodies at temperatures T1, T2 and T3 respectively are as shown. Their temperature are such that
The plots of intensity versus wavelength for three black bodies at temperatures T1, T2 and T3 respectively are as shown. Their temperature are such that
physics-General
physics-
The graph. Shown in the adjacent diagram, represents the variation of temperature (T) of two bodies, x and y having same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity (e) and absorptivity (a) of the two bodies
The graph. Shown in the adjacent diagram, represents the variation of temperature (T) of two bodies, x and y having same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity (e) and absorptivity (a) of the two bodies
physics-General
