A beaker containing a liquid is kept inside a big closed jar. If the air inside the jar is continuously pumped out, the pressure in the liquid near the bottom of the beaker will
1. Increase
2. Decrease
3. Remain constant
4. First decrease and then increase

A vertical \(\mathrm{U}\)-tube of uniform inner cross-section contains mercury in both its arms. A glycerin (density\(=1.3\) g/cm³) column of length \(10\) cm is introduced into one of its arms. Oil of density \(0.8\) g/cm³  is poured into the other arm until the upper surfaces of the oil and glycerin are at the same horizontal level. The length of the oil column is:
(density of mercury \(=13.6\) g/cm³)
                       
1. \(10.4\) cm
2. \(8.2\) cm
3. \(7.2\) cm
4. \(9.6\) cm

If two liquids of same masses but densities ${\mathrm{\rho }}_1$ and ${\mathrm{\rho }}_2$ respectively are mixed, then density of mixture is given by

(1) $\mathrm{\rho }=\frac{{\mathrm{\rho }}_1+{\mathrm{\rho }}_2}{2}$                             

(2) $\mathrm{\rho }=\frac{{\mathrm{\rho }}_1+{\mathrm{\rho }}_2}{2{\mathrm{\rho }}_1{\mathrm{\rho }}_2}$

(3) $\mathrm{\rho }=\frac{2{\mathrm{\rho }}_1{\mathrm{\rho }}_2}{{\mathrm{\rho }}_1+{\mathrm{\rho }}_2}$                             

(4) $\mathrm{\rho }=\frac{{\mathrm{\rho }}_1{\mathrm{\rho }}_2}{{\mathrm{\rho }}_1+{\mathrm{\rho }}_2}$

For the figures given below, the correct observation is:
              

A metallic block of density 5 gm ${\mathrm{cm}}^{-3}$ and having dimensions 5 cm × 5 cm × 5 cm is weighed in water. Its apparent weight will be

(2) 5 × 5 × 5 × 5 gf                           

(3) 4 × 4 × 4 × 4 gf

(4) 5 × 4 × 4 × 4 gf                           

(d) 4 × 5 × 5 × 5 gf

A hollow sphere of volume V is floating on water surface with half immersed in it. What should be the minimum volume of water poured inside the sphere so that the sphere now sinks into the water ?
(1) V/2                       

(2) V/3

(3) V/4                       

(4) V

A boat carrying steel balls is floating on the surface of water in a tank. If the balls are thrown into the tank one by one, how will it affect the level of water?

Construction of submarines is based on 
(1) Archimedes’ principle               

(2) Bernoulli’s theorem

(3) Pascal’s law                             

(4) Newton’s laws

The velocity of kerosene oil in a horizontal pipe is 5 m/s. If $\mathrm{g}=10\mathrm{m}/{\mathrm{s}}^2$, then the velocity head of oil will be:
1. 1.25 m
2. 12.5 m
3. 0.125 m                             
4. 125 m

A barometer kept in a stationary elevator reads 76 cm. If the elevator starts accelerating up, the reading will be
(1) Zero                                       

(2) Equal to 76 cm

(3) More than 76 cm                     

(4) Less than 76 cm