# Lesson Archives

1. ## Solutions Chapter 4 – Atoms

Page No 435: Question 12.1: Choose the correct alternative from the clues given at the end of the each statement: (a) The size of the atom in Thomson’s model is ………. the atomic size in Rutherford’s model. (much greater than/no different from/much less than.) (b) In the ground state of ………. electrons are in stable equilibrium, while […]
2. ## Solutions Chapter 3 – Dual Nature Of Radiation And Matter

Page No 407: Question 11.1: Find the (a) maximum frequency, and (b) minimum wavelength of X-rays produced by 30 kV electrons. Answer: Potential of the electrons, V = 30 kV = 3 × 104 V Hence, energy of the electrons, E = 3 × 104 eV Where, e = Charge on an electron = 1.6 × 10−19 C (a)Maximum frequency produced by the X-rays = ν […]
3. ## Solutions Chapter 2 – Wave Optics

Page No 383: Question 10.1: Monochromatic light of wavelength 589 nm is incident from air on a water surface. What are the wavelength, frequency and speed of (a) reflected, and (b) refracted light? Refractive index of water is 1.33. Answer: Wavelength of incident monochromatic light, λ = 589 nm = 589 × 10−9 m Speed of […]
4. ## Solutions Chapter 1 – Ray Optics And Optical Instruments

Page No 345: Question 9.1: A small candle, 2.5 cm in size is placed at 27 cm in front of a concave mirror of radius of curvature 36 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? Describe the nature and size of the image. […]
5. ## Part II

Chapter 1 – Ray Optics And Optical Instruments Chapter 2 – Wave Optics Chapter 3 – Dual Nature Of Radiation And Matter Chapter 4 – Atoms Chapter 5 – Nuclei Chapter 6 – Semiconductor Electronics: Materials Devices and Simple Circuits Chapter 7 – Communication Systems
6. ## Solutions Chapter 8 – Electromagnetic Waves

Page No 285: Question 8.1: Figure 8.6 shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A. (a) Calculate the capacitance and the rate […]
7. ## Solutions Chapter 7 – Alternating Current

Page No 266: Question 7.1: A 100 Ω resistor is connected to a 220 V, 50 Hz ac supply. (a) What is the rms value of current in the circuit? (b) What is the net power consumed over a full cycle? Answer: Resistance of the resistor, R = 100 Ω Supply voltage, V = 220 V Frequency, ν = 50 Hz (a) The rms value […]
8. ## Solutions Chapter 6 – Electromagnetic Induction

Page No 229: Question 6.1: Predict the direction of induced current in the situations described by the following Figs. 6.18(a) to (f ). (a) (b) (c) (d) (e) (f) Answer: The direction of the induced current in a closed loop is given by Lenz’s law. The given pairs of figures show the direction of the […]
9. ## Solutions Chapter 5 – Magnetism And Matter

Page No 200: Question 5.1: Answer the following questions regarding earth’s magnetism: (a) A vector needs three quantities for its specification. Name the three independent quantities conventionally used to specify the earth’s magnetic field. (b) The angle of dip at a location in southern India is about 18º. Would you expect a greater or smaller dip angle […]
10. ## Solutions Chapter 4 – Moving Charges And Magnetism

Page No 169: Question 4.1: A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the centre of the coil? Answer: Number of turns on the circular coil, n = 100 Radius of each turn, r = 8.0 cm = 0.08 […]