A farsighted boy has a near point at 2.3 m and requires ...

[bobbie]

A farsighted boy has a near point at 2.3 m and requires eyeglasses to correct his vision. Corrective lenses are available in increments in power of 0.25 diopters.
 
  The eyeglasses should have lenses of the lowest power for which the near point is no further than 25 cm. The correct choice of lens power for eyeglasses, in diopters, is: A) +3.75
  B) +3.50
  C) +3.25
  D) +4.00
  E) +4.25

Question 2

Four equal +6.00-C point charges are placed at the corners of a square 2.00 m on each side. (k = 1/40 = 8.99  109 N  m2/C2)
 
  (a) What is the electric potential (relative to infinity) due to these charges at the center of this square?
  (b) What is the magnitude of the electric field due to these charges at the center of the square?

[sultansheikh]

Answer to Question 1

A

Answer to Question 2

(a) 153 kV (b) zero

[bobbie]

Gracias!

[raenoj]

Thanks for the timely response, appreciate it