One mole of Strontium-90 is decaying with a half life of 28. ...

[washai]

One mole of Strontium-90 is decaying with a half life of 28. years. After 61. years, how much Strontium is left and what is its activity?
 
  What will be an ideal response?

Question 2

A very fine sample is placed 0.15 cm from the objective of a microscope. The focal length of the objective is 0.14 cm and of the eyepiece is 1.0 cm. The near-point distance of the person using the microscope is 25.0 cm.
 
  What is the final magnification of the microscope? A) -375
  B) -242
  C) -108
  D) -142
  E) -100

[Koolkid240]

Answer to Question 1

0.22 mole; 5.5  10-3 mole/yr = 1.0  1014 Becquerel = 2.8  103 Curie

Answer to Question 2

A

[washai]

Excellent

[xthemafja]

Thanks for the timely response, appreciate it