A 7.0- resistor is connected across the terminals of a battery ...

[dmcintosh]

A 7.0- resistor is connected across the terminals of a battery having an internal emf of 10 V. If there is a 0.50-A current through the circuit, what is the internal resistance of the battery?
 
  A) 13
  B) 20
  C) 10.8
  D) 27.0

Question 2

A thin uniform film of oil that can be varied in thickness covers a sheet of glass of refractive index 1.52.
 
  The refractive index of the oil is 1.64. Light of wavelength 555 nm is shone from air at normal incidence on the film. Starting with no oil on the glass, you gradually increase the thickness of the oil film until the first interference maximum in the reflected light occurs. What is the thickness of the oil film at that instant?
  A) 139 nm
  B) 169 nm
  C) 183 nm
  D) 84.6 nm
  E) 91.3 nm

[k2629]

Answer to Question 1

A

Answer to Question 2

D

[dmcintosh]

Thanks for the timely response, appreciate it

[yeungji]

Wow, this really help