The speed of air flows on the upper and lower surfaces of a wing of an aeroplane are v1 and v2 respectively. If A is the cross section area of the wing and ρ is the density of air, then the upward life is
The work done in increasing the size of a soap film for 10cm × 6cm to 10cm × 11cm is 3 × 10-4 J. The surface tension of the film is
1.0 × 10-2 N/m
6.0 × 10-2 N/m
3.0 × 10-2 N/m
1.5 × 10-2 N/m
For a gas = 0.67. This gas is made up of molecules which are
monoatomic
polyatomic
mixture of diatomic and polyatomic molecules
diatomic
A transverse wave is represented by the equation . For what value of is the particle velocity equal to two times the wave velocity
Two simple pendulums of length 0.5 m and 20 m respectively are given small linear displacement in one direction at the same time. They will again be in the phase when the pendulum of shorter length has
completed x oscillations, where k is
1
3
2
5
A balloon contains 500 m3 of helium at 27o C and 1 atmosphere pressure. The volume of the helium at - 3° C temperature and 0.5 atmosphere pressure will be
1000 m3
900 m3
700 m3
500 m3
A black body has a wavelength of ) λ at temperature 2000 K. Its corresponding wavelength at temperature 3000 K will be
An ice-cube of density 900 kg/m3 is floating in water of density 1000 kg/m3. The percentage of volume ofice-cube outside the water is
20%
35%
10%
25%
C.
10%
The percentage of volume of ice cube outside the water is
=
=
= 10 %
A parallel palte condenser is filled with two dielectrics as shown in figure. Area of each pate is A m2 and the separation is d metre. The dielectric constants are K1 and K2 respectively. Its capacitance in farad will be
A battery of emf 10 V and internal resistance of 0.5 ohm is connected across a variable resistance R. The maximum value of R is given by
0.5 Ω
1.00 Ω
2.0 Ω
0.25 Ω