Most modern electronic devices contain a touchscreen - Leaving Cert Physics - Question 9 - 2014

To demonstrate an electric field pattern:

1. Set up two parallel metal plates connected to a high voltage source.
2. Place a piece of cardboard on top of the plates, sprinkle fine iron filings over the cardboard.
3. Turn on the voltage; the filings will align along the electric field lines, demonstrating the electric field pattern.
4. Observe that the filings are denser between the plates and sparser further away, illustrating the field's strength.

Using the formula for capacitance:

$C = \frac{Q}{V}$

where ( C = 12 \mu F = 12 \times 10^{-6} F ) and ( V = 6 V ):

Rearranging gives:

$Q = C \times V = 12 \times 10^{-6} F \times 6 V = 72 \mu C$

The energy stored in a capacitor is given by:

$E = \frac{1}{2} C V^2$

Plugging in the values:

$E = \frac{1}{2} \times 12 \times 10^{-6} F \times (6 V)^2 = 216 \mu J$

When the distance ( d ) is increased by a factor of three, the new capacitance ( C' ) can be calculated by:

$C' = \frac{C}{3} = \frac{12 \mu F}{3} = 4 \mu F$

1. Discharge Rate: A capacitor discharges faster than a battery, delivering energy rapidly, whereas a battery provides a constant current over time.
2. Energy Storage: A capacitor stores electrostatic potential energy, while a battery stores chemical energy.

Polarisation of light refers to the orientation of the oscillations of the light waves in a particular direction. When light is polarised, its waves vibrate in one plane as opposed to vibrating in multiple planes.

One application of capacitors is in flash circuits for cameras, where they store energy and release it quickly to generate a bright flash.