Understanding Radioactivity Units: The Rutherford Explained

Radioactivity is the spontaneous process by which an unstable atomic nucleus loses energy by emitting radiation. This process is also called radioactive decay or nuclear disintegration. The rate at which these disintegrations occur is a measure of the activity of a radioactive substance.

Several units are used to quantify radioactivity. The standard international (SI) unit for radioactivity is the becquerel (Bq), which is defined as one disintegration per second. Another unit, which is older but still sometimes used, is the curie (Ci), related to the activity of one gram of radium-226.

The question asks about the Rutherford (Rd), another unit of radioactivity. The Rutherford was proposed as a unit of radioactivity activity.

Let's look at the definition of one Rutherford:

• One Rutherford (1 Rd) is defined as the quantity of radioactive material in which \(10^6\) nuclei disintegrate per second.

This definition directly relates the Rutherford unit to the number of disintegrations per unit time. Comparing this definition to the given options:

• Option 1: \(10^8\) disintegrations per second
• Option 2: \(10^4\) disintegrations per second
• Option 3: \(10^6\) disintegrations per second
• Option 4: 1 disintegration per second

Based on the definition, one Rutherford is equal to \(10^6\) disintegrations per second.

We can also compare Rutherford with other units:

• 1 Becquerel (Bq) = 1 disintegration per second
• 1 Curie (Ci) \(\approx 3.7 \times 10^{10}\) disintegrations per second
• 1 Rutherford (Rd) = \(10^6\) disintegrations per second

From this comparison, it's clear that 1 Rutherford corresponds to \(10^6\) disintegrations per second.

Therefore, one Rutherford is equal to \(10^6\) disintegrations per second.

Revision Table: Radioactivity Units and Rutherford

Let's quickly review the key points about the Rutherford unit:

• Unit Name: Rutherford
• Symbol: Rd
• Definition: Activity of a radioactive substance undergoing \(10^6\) nuclear disintegrations per second.
• Relation to Becquerel: \(1 \text{ Rd} = 10^6 \text{ Bq}\)
• Historical Context: An older unit, less commonly used than the Becquerel or Curie today.

Additional Information: Understanding Radioactive Disintegration

Radioactive disintegration, also known as radioactive decay, is a fundamental process in nuclear physics. It's the process by which an unstable atomic nucleus spontaneously transforms into a different nucleus (or a different energy state of the same nucleus) by emitting particles and/or energy. The rate of disintegration, or activity, is a measure of how many such decay events occur per unit time in a sample of radioactive material.

Key aspects of radioactive disintegration:

• Spontaneous Process: Decay happens randomly for individual nuclei, but the rate for a large number of nuclei is predictable.
• Types of Decay: Common types include alpha decay (\(\alpha\)), beta decay (\(\beta\)), and gamma decay (\(\gamma\)).
• Half-Life: Each radioactive isotope has a characteristic half-life, which is the time it takes for half of the radioactive nuclei in a sample to decay.
• Activity Measurement: Activity is measured in disintegrations per second (dps) or related units like Becquerel (Bq), Curie (Ci), or Rutherford (Rd). Higher activity means more disintegrations per second, indicating a more rapidly decaying substance or a larger quantity of the substance.

Understanding the concept of disintegrations per second is crucial for quantifying the rate of radioactive decay, and units like Rutherford provide a specific measure for this rate.