1. **Problem statement:** Two point charges each of $2.19\,\mu C$ are located on the x-axis at $x=1.13\,m$ and $x=-1.13\,m$. We need to find the electric field at the point on the y-axis at $y=0.474\,m$.
2. **Formula for electric field due to a point charge:**
The electric field $\vec{E}$ at a distance $r$ from a point charge $q$ is given by
$$\vec{E} = \frac{k |q|}{r^2} \hat{r}$$
where $k = 8.99 \times 10^9 \ N \cdot m^2/C^2$ is Coulomb's constant, and $\hat{r}$ is the unit vector from the charge to the point of interest.
3. **Calculate distance from each charge to the point on y-axis:**
Each charge is at $(\pm 1.13, 0)$ and the point is at $(0, 0.474)$.
Distance $r = \sqrt{(1.13)^2 + (0.474)^2} = \sqrt{1.2769 + 0.2245} = \sqrt{1.5014} \approx 1.225\,m$.
4. **Calculate magnitude of electric field from one charge:**
$$E = \frac{8.99 \times 10^9 \times 2.19 \times 10^{-6}}{(1.225)^2} = \frac{1.968 \times 10^4}{1.5014} \approx 1.31 \times 10^4 \ N/C$$
5. **Determine direction of electric field vectors:**
The two charges are positive, so the electric field at the point due to each charge points away from the charge.
The x-components of the fields from the two charges cancel because they are equal in magnitude and opposite in direction.
The y-components add up.
6. **Calculate y-component of electric field from one charge:**
The angle $\theta$ between the line connecting charge to point and the x-axis is
$$\theta = \tan^{-1}\left(\frac{0.474}{1.13}\right) \approx 22.8^\circ$$
7. **Calculate total electric field on y-axis:**
The y-component from one charge is
$$E_y = E \sin \theta = 1.31 \times 10^4 \times \sin 22.8^\circ \approx 1.31 \times 10^4 \times 0.388 = 5.08 \times 10^3 \ N/C$$
Since there are two charges, total $E_y = 2 \times 5.08 \times 10^3 = 1.02 \times 10^4 \ N/C$.
**Final answer:** The electric field at $y=0.474\,m$ on the y-axis is approximately
$$\boxed{1.02 \times 10^4 \ N/C \text{ directed along positive y-axis}}$$
Electric Field Yaxis 1B5D30
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.