Question Library

No expanded working has been attached for this question yet. The verified answer is Option D.

No expanded working has been attached for this question yet. The verified answer is Option B.

Using wheatstone bridge principle; \(\frac{2}{x} = \frac{2}{(100 - x)}\) 2(100 - x) = 2 x \(x\) 200 = 2\(x + 2x\) 200 = 4x x = \(\frac{200}{4}\) = 50cm

No expanded working has been attached for this question yet. The verified answer is Option D.

Centripetal force (Fr) = \(\frac{MV^2}{r}\) i.e. Fr = \(\frac{Mv^2}{r}\) = \(\frac{9.1 \times 10^{-31} \times 2.0 \times 10^6 \times 2.0 \times 10^6}{6.1 \times 10^{-11}}\) N = (\(\frac{36.4 \times 10^{-19}}{6.1 \times 10^{-11}}\)) N = 5.967 x 10\(^{-8}\) N ~ 6.0 x 10\(^{-8}\) N

Cold water has a higher surface tension than soapy water, hot water, and oily water. Soapy water has surfactants that reduce surface tension, while hot water has lower surface tension than cold water due to increased molecular motion. Oily water also has a lower surface tension than pure water.

Neutron No (N) = 238 - 92 = 146

No expanded working has been attached for this question yet. The verified answer is Option D.

Photoelectrons are electrons that are ejected from a material (usually a metal) when it absorbs photons of light, such as ultraviolet light. This phenomenon is known as the photoelectric effect.

Since the substance is solid, it will need heat to melt to liquid and once the liquid starts boiling temperature will remain the same.

(a) The emission of light from a substance when its excited electrons move to a lower energy level. OR Distinct/separate bright lines of light of definite frequency/wavelength (emitted from vapourised atoms) (ii) Emission spectra is the pattern of light displayed when electrons jump from a higher energy level to a lower energy level, while absorption spectra is the displayed pattern of wavelengths absorbed by the gas. (b) \(\Delta\)E = E\(_i\) - E\(_f\) = -1.51 + 13.6 = 12.09 eV = 12.09 x 1.6 x 10\(^{-19}\) J = 1.934 x 10\(^{-18}\) J (ii) \(\Delta\)E- hf f = \(\frac{\Delta E}{h}\) = \(\frac{1.934 \times 10^{-18}}{6.6 \times 10^{-34}}\) f = 2.93 x 10\(^{15}\)Hz (ii) c = f\(\lambda\) \(\lambda\) = \(\frac{3 \times 10^8}{2.93 x 10^{13}}\) = 1.023 x 10\(^{-7}\)m (c) (I) Soft x-rays are those with longer wavelengths/lowNer penetrating/less energy while hard x-rays are those with shorter wavelengths/higher penetrating power more energy. (iii) To increase the electrical conductivity/reduce electrical resistivity of the semiconductor.

Using the formula F = \(\frac{Gm_1m_2}{r^2}\) = \(\frac{6.67 \times 10^{-11} \times 3.0 \times 2.0}{(50)^2}\) = \(\frac{40.02 \times 10^{-11}}{2500}\) = 1.6 x 10\(^{-9}\)N

for an object moving along a circular path, it speed is constant but its linear velocity changes with time at every point on the circle.

frequency means no of oscillation per secs, so the time taken to trace a wave between p and q is 2secs.

No expanded working has been attached for this question yet. The verified answer is Option A.