Example 1A mercury manometer with one end attached to a gas supply measures a difference in the level of mercury of 32 cm as shown in figure below

Calculate the pressure of the gas supply in (a)cm Hg(b)Pascal

[Patm=76 cm Hg,g =9.8N kg -1,ρHg = 1.36 x 10 4kg m-3]

Solution (a) Pg = Patm + Pressure due to the column of mercury

= 76 cm Hg + 32 cm Hg= 108 cm Hg

(b) Pg = 108/100 x 1.36 x 104 x 9.8

= 1.44 x 105 Pa

• Rajah menunjukkan barometer merkuri. Hitung tekanan atmosfera dalam unit….

(a) cm Hg(b) Pa[ρHg=13600kg m-3, g=10N kg-1]

• Solution:(a) Patm = 76 cm Hg

(b) Patm = ρhg

= 13600 x 0.76 x 10 = 1.03 x 105 Pa

• Hitung tekanan gas yang terperangkap didalam merkuri bagi setiap kes di bawah :

tekanan atmosfera = 75 cm

Hg

Solution ;

(a) Pg = Patm - 3 (b) Pg=Patm (c) Pg= Patm + 3

Pg= 75 – 3 Pg= 75 cm Hg Pg= 75 + 3

Pg= 72 cm Hg Pg= 78 cm Hg