A manometer consists of a u-shaped tube containing a liquid. One side is connected to the appratus and other is open to the atnosphere. The pressure inside the appratus is then determined from the difference in heights of the liquid. The external pressure is 760 torr and density of liquid is 10gm cm^-3. The open side is 10.0 cm lower than the side connected to the appratus. The pressure in the appratus is (approx).

1)605.5 torr
2)685.5 torr
3)714.5 torr
4)720.1 torr

Dear student,


Here, density of oil,  r = 10 g/cm³ = 10⁴ kg/m³ 
Height, h = 10 cm = 0.1 m
Hence, the pressure exerted by 10 cm (0.1 m) liquid   =  r gh 
                                                                                      = (10⁴ kg/m³)(9.8m/s²)(0.1m)
                                                                                      = 9800 Pa
                                                                                      = 0.09674 atm
                                                                                      = 73.5224 torr
Therefore, pressure inside the apparatus = 760 - 73.5224
                                                                  = 686.4776 (approx)

Regards