Question

. Force necessary to pull a circular plate of 5
cm radius from water surface for which
surface tension is 75 dynes/cm, is
A) 30 dyne B) 750 dynes
C) 60 dynes D) 750 dynes
and explain​

Answer 1

Step-by-step explanation:

Given Force necessary to pull a circular plate of 5  cm radius from water surface for which  surface tension is 75 dynes/cm, is

• We have a circular plate of 5 cm radius.
• The total length of circular plate on which the force will act will be 2πr
• So force necessary to pull will be T x 2πR (circumference of circle)
•                                                       = 75 x 2π x 5
•                                                          = 750 π  dynes
•                                                         = 2355 dynes.
•                                                      1 dyne = 10^-5 N
•                                                     2355 dyne = 2355 x 10^-5 N

750  π  dynes is the force required to pull the circular plate.