(a) Interpretation: The counting rate 9cpm is the background counting rate in the laboratory which was measured at the time period of 3 min and it is required that the value of standard relative deviation should be less than the 5% ( σ R c / R c < 0.05 ) . The total number of count is to be determined when the counting rate is 50cpm. Concept introduction: The formula for the standard deviation for the corrected counting rate is given as- σ R c = R x t x + R b t b ……. (1) Where, R x = counting rate for sample R b = counting rate for background t x = time required for counting rate for sample t b = time required for counting rate for background σ R c = standard deviation for the corrected counting rate Relative standard deviation is represented by the following formula- = σ R c R c …… (2) Also, R c = R x − R b

BuyFind

Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213
BuyFind

Principles of Instrumental Analysis

7th Edition
Douglas A. Skoog + 2 others
Publisher: Cengage Learning
ISBN: 9781305577213

Solutions

Chapter 32, Problem 32.8QAP
Interpretation Introduction

(a)

Interpretation:

The counting rate 9cpm is the background counting rate in the laboratory which was measured at the time period of 3 min and it is required that the value of standard relative deviation should be less than the 5% (σRc/Rc<0.05). The total number of count is to be determined when the counting rate is 50cpm.

Concept introduction:

The formula for the standard deviation for the corrected counting rate is given as-

σRc=Rxtx+Rbtb ……. (1)

Where,

Rx = counting rate for sample

Rb = counting rate for background

tx = time required for counting rate for sample

tb = time required for counting rate for background

σRc = standard deviation for the corrected counting rate

Relative standard deviation is represented by the following formula-

=σRcRc …… (2)

Also,

Rc=RxRb

Interpretation Introduction

(b)

Interpretation:

The counting rate 9cpm is the background counting rate in the laboratory which was measured at the time period of 3 min and it is required that the value of standard relative deviation should be less than the 5% (σRc/Rc<0.05). The total number of count is to be determined when the counting rate is 300cpm.

Concept introduction:

The formula for the standard deviation for the corrected counting rate is given as-

σRc=Rxtx+Rbtb ……. (1)

Where,

Rx = counting rate for sample

Rb = counting rate for background

tx = time required for counting rate for sample

tb = time required for counting rate for background

σRc = standard deviation for the corrected counting rate

Relative standard deviation is represented by the following formula-

=σRcRc …… (2)

Also,

Rc=RxRb

Want to see the full answer?

Check out a sample textbook solution.

Want to see this answer and more?

Experts are waiting 24/7 to provide step-by-step solutions in as fast as 30 minutes!*

*Response times may vary by subject and question complexity. Median response time is 34 minutes for paid subscribers and may be longer for promotional offers.