Use of eddy is done on the following except :

Options

A. moving coil galvanometer
B. electric brakes
C. induction motor
D. dynamo

Answer

To solve the question about the uses of eddy currents, we need to analyze the options provided and identify which one does not utilize eddy currents.

### Step-by-Step Solution:

1. **Understanding Eddy Currents**: Eddy currents are loops of electric current that are induced within conductors by a changing magnetic field in the conductor. They can create magnetic fields that oppose the change in the magnetic field that produced them, leading to energy loss in the form of heat.

2. **Analyzing Each Option**:
- **Moving Coil Galvanometer**: This device uses a coil in a magnetic field, and when current flows through the coil, it experiences torque due to the magnetic field. Eddy currents can be present in the coil, so this option does utilize eddy currents.

- **Induction Motor**: An induction motor operates on the principle of electromagnetic induction, where eddy currents are induced in the rotor. Therefore, this option also utilizes eddy currents.

- **Dynamo**: A dynamo converts mechanical energy into electrical energy using a rotating coil in a magnetic field. The primary function is to induce current in the coil, but it does not rely on the generation of eddy currents for its operation. Instead, it focuses on the induced electromotive force (EMF) in the coil. Thus, this option does not utilize eddy currents.

- **Electric Braking**: In electric braking systems, eddy currents are generated in the braking material, which helps in slowing down the motion of the vehicle due to the opposing magnetic fields created by the eddy currents. Hence, this option does utilize eddy currents.

3. **Conclusion**: Based on the analysis, the option that does not utilize eddy currents is the **Dynamo**.

### Final Answer:
The use of eddy currents is done on the following except: **Dynamo**.

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