Photographic plates and films have an essential ingredient of

Options

A. silver nitrate
B. silver bromide
C. sodium chloride
D. oleic acid

Explanation

To solve the question regarding the essential ingredient in photographic plates and films, we can follow these steps:

### Step 1: Understand the Composition of Photographic Plates and Films
Photographic plates and films are made up of a glass plate or a thin strip of celluloid that is coated with a light-sensitive emulsion.

**Hint:** Look for the materials that are known to be light-sensitive and commonly used in photography.

### Step 2: Identify the Common Light-Sensitive Compounds
The options given are:
1. Silver nitrate (AgNO₃)
2. Silver bromide (AgBr)
3. Silver sodium chloride (AgCl)
4. Oleic acid

Among these, silver compounds are known for their photosensitivity.

**Hint:** Consider which silver compound is specifically known for its use in photography.

### Step 3: Analyze Each Option
- **Silver Nitrate (AgNO₃):** While it is a silver compound, it is not primarily used in photographic films.
- **Silver Bromide (AgBr):** This compound is known for its high photosensitivity and is widely used in photographic emulsions.
- **Silver Sodium Chloride (AgCl):** This is less common in photographic applications compared to silver bromide.
- **Oleic Acid:** This is not a silver compound and is not used in photographic plates or films.

**Hint:** Focus on the silver compound that is specifically mentioned in the context of photographic emulsions.

### Step 4: Conclusion
Based on the analysis, the essential ingredient in photographic plates and films is **Silver Bromide (AgBr)**.

### Final Answer:
The correct answer is **Silver Bromide (AgBr)**.

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