Step 1: The given differential equation is: \[ y \, dx + x \, \log{\left(\frac{y}{x}\right)} \, dy - 2x \, dy = 0 \] Rewriting it, we get: \[ y \, dx + \left( x \log{\left(\frac{y}{x}\right)} - 2x \right) dy = 0 \]
Step 2: The equation is of the first order as the highest derivative involved is \( \frac{dy}{dx} \).
Step 3: The equation does not involve any fractional power of the highest derivative, and the degree is the exponent of the highest derivative, which is 1.
A battery of emf \( E \) and internal resistance \( r \) is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of \( E \) and \( r \).