An iron ring measuring 15.00 cm in diameter is a be shrunk on a pulley which is 15.05 cm in diamer. All measurements refer to the room temperature `20^0 C`. To What minimum temperature should the ring be heated to make the job possible? Calculate the strain developed in the ring when in comes to the room temperature. Coefficient of linear expansion of iron `=12 xx 10^(-6) ^0 C^(-1)`.

Explanation

To solve the problem step by step, we will first determine the minimum temperature to which the iron ring must be heated in order to fit onto the pulley, and then we will calculate the strain developed in the ring when it returns to room temperature.

### Step 1: Understand the Problem
The iron ring has a diameter of 15.00 cm, and the pulley has a diameter of 15.05 cm. The goal is to find out the minimum temperature to which the ring must be heated so that it can fit onto the pulley.

### Step 2: Use the Linear Expansion Formula
The formula for linear expansion is given by:
\[
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