Two temperature scales A and B are related by . At which temperature two scales have the same reading ?
− 42°
− 72°
+ 12°
− 40°
An ideal gas is compressed isothermally until its pressure is doubled and then allowed to expand adiabatically to regain its original volume (γ = 1.4 and 2-1.4 = 0.38). The ratio of the final to initial pressure is
0.76 : 1
1 : 1
0.66 : 1
0.86 : 1
Air inside a closed container is saturated with water vapour. The air pressure is p and the saturated vapour pressure of water is . If the mixture is compressed to one-half of its volume by maintammg temperature constant, the pressure becomes
1.56 x 105 J of heat is conducted through a 2 m2 wall of 12 cm thick in 1 h. Temperature difference between the two sides of the wall is 20° C. The thermal conductivity of the material of the wall is (in W m-1 K-1)
0.11
0.13
0.15
1.2
Five equal resistance, each of resistance R are connected as shown in figure below. A battery of V volt is connected between A and B. The current flowing in FC will be
Two cells with the same emf E and different internal resistances r1 and r2 are connected in series to an external resistance R. The value of R so that the potential difference across the first cell be zero, is
r1 + r2
r1 − r2
C.
r1 − r2
There are two batteries with emf E each and the internal resistances r1 and r2 respectively. Hence we have I (R + r1 + r2) = 2E
thus,
Now the potential difference across the first cell would be equal to V = E − Ir1. From the question, V = 0, hence E = Ir1 = , thus R + r1 + r2 = 2r1, hence R = r1 − r2
Current through ABC and A' B'C' is I. What is the magnetic field at P ? BP = PB' = r (Here C' B' PBC are collinear)
Zero