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The charge of a body is determined by the imbalance between the number of protons (positively charged) and electrons (negatively charged). A deficiency of electrons results in a positive charge, while a surplus of electrons results in a negative charge.

In many AC radio circuits, transformers are used primarily to reduce the voltage to levels suitable for safe and effective operation of the components.

Electrical power = IV or I2R or (V)/R With V = 240v, R = 960Ω Power (V2)/R = (240 X 240)/960 =60Watts

In a variable capacitor, the capacitance is adjusted by changing the overlapping area of the plates (area) and/or the distance between the plates (distance). This allows for tuning in radio sets.

In a capacitive circuit, current leads voltage by 90°, or voltage lags current by 90°

Power of heater = lvt = 2 x 240 x t heat required to boil the water = Mct = 2.5 x 4.2 x 103 x (100.52) = 2.5 x 4. 2 x 103 x 48 2 x 240 x t = 2.5 x 4.2 x 103 x 48 ∴ t = (2.5 x 4.2 x 103 x 48)/2 x 240 = 1050s or 1.05 x 103s

The thermos flask is designed to: A. prevent heat loss or gain by conduction, convection, and radiation Its design minimizes heat transfer in all three forms, keeping liquids hot or cold for extended periods.

when the glass of a thermometer expands more on heating than the liquid inside, the liquid level would fall compared with the tube wall

This process occurs as the petrol evaporates, drawing heat away from the skin and causing a cooling sensation.

Power = I\(^2\)R = \((\frac{E}{R + r})^2 R\) To get point of maximum power transfer, we take the derivative and equate it to 0. \(P = E^2 (\frac{R}{(R + r)^2})\) \(\frac{\mathrm d P}{\mathrm R} = E^2 (\frac{(R + r)^2 - 2R(R + r)}{(R + r)^4})\) = \(E^2 (\frac{(R + r)[(R + r) - 2R}{(R + r)^4})\) \(\frac{\mathrm d P}{\mathrm d R} = E^2 (\frac{r - R}{(R + r)^3})\) Maximum power is gotten when r - R = 0 i.e. r = R.

In a nickel-iron (NiFe) accumulator, the electrolyte used is typically a potassium hydroxide solution.

M = Itz; z = (M)/It = (2)/0.5 x 3 x 60 x 60 = 3.703 x 10-4 gc-1 ∴ M = Itz = 1.5 x 1 x 60 x 60 x 3.703 x 10-4 = 1.99962g. =2.0g

The r.m.s value of an a.c voltage/current is the value of the d.c. voltage/ current that will dissipate the same amount of energy in a given resistance as the a.c. Thus the r.m.s value of the a.c supply is 12v.

R\(_s\) = \(\frac{(i_gr_g)}{I-i_g}\) = \(\frac{(50 \times 10^{-3} \times 5)}{5 - (50 x 10^{-3})}\) = \(\frac{(0.25)}{4.95}\) = 0.0505 = 0.05Ω

Generally, the viscosity of liquids tends to increase with pressure, as the increased pressure can lead to a greater interaction between molecules