A flat plate of area $10\,cm^2$  is separated from a large plate by a layer of glycerine $1\, mm$ thick. If the coefficient of viscosity of glycerine is $20$  poise, the force required to keep the plate moving with a velocity of  $1\,cm/sec$  is .......... $dyne$
  • A$80$
  • B$200$
  • C$800$
  • D$2000$
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