CBSE Class 12 Physics Lens and Mirror

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NCERT Solutions Class 12 Physics Chapter 14 Semiconductor Electronics Materials Devices And Simple Circuits

Question. In an n-type silicon, which of the following statement is true: (a) Electrons are majority carriers and trivalent atoms are the dopants. (b) Electrons are minority carriers and pentavalent atoms are the dopants. (c) Holes are minority carriers and pentavalent atoms…

NCERT Solutions Class 12 Physics Chapter 10 Wave Optics

Question : Monochromatic light having a wavelength of 589nm from the air is incident on a water surface. Find the frequency, wavelength and speed of (i) reflected and (ii) refracted light? [1.33 is the Refractive index of water] Answer : Monochromatic light incident…

NCERT Solutions Class 12 Physics Chapter 9 Ray Optics And Optical Instruments

Question. 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. If the candle is moved…

NCERT Solutions Class 12 Physics Chapter 4 Moving Charges And Magnetism

Question : 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 : Given: Number of turns, n = 100 Radius of coil, r = 8 cm Current through…

NCERT Solutions Class 12 Physics Chapter 5 Magnetism And Matter

Question. 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…

NCERT Solutions Class 12 Physics Chapter 2 Electrostatic Potential And Capacitance

Question 2.1: Two charges 5 × 10−8 C and −3 × 10−8 C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero. Answer There are two charges, q1 = 5 x 10-8 C q2…

NCERT Solutions Class 12 Physics Chapter 8 Electromagnetic Waves

Question. Two circular plates having radius of 12 cm each and separated by 5 cm are used to make a capacitor as shown in the Figure 8.6. An external source charges this capacitor. 0.15 A is the charging current which remains constant. (a) Determine the capacitance and the…

NCERT Solutions Class 12 Physics Chapter 6 Electromagnetic Induction

Question : Predict the direction of induced current in the situations described by the following Figs. 6.18(a) to (f ). (a) Answer : Lenz’s law shows the direction of induced current in a closed loop. In the given two figures they shows the direction of induced…

NCERT Solutions Class 12 Physics Chapter 1 Electric Charges And Fields

Question. What is the force between two small charged spheres having charges of 2 × 10−7 C and 3 × 10−7 C placed 30 cm apart in air? Answer : Repulsive force of magnitude 6 × 10−3 N Charge on the first sphere, q1 = 2 × 10−7 C Charge on the…

NCERT Solutions Class 12 Physics Chapter 3 Current Electricity

Question. The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4Ω, what is the maximum current that can be drawn from the battery? Answer : Given that Emf of the battery, E = 12 V Battery has an Internal resistance of R = 0.4 Ω…

NCERT Solutions Class 12 Physics Chapter 15 Communication Systems

Question. Which of the following frequencies will be suitable for beyond-the-horizon communication using sky waves?  (a) 10 kHz (b) 10 MHz (c) 1 GHz (d) 1000 GHz Answer : B For beyond-the-horizon communication, it is necessary for the signal waves to travel a large…

NCERT Solutions Class 12 Physics Chapter 7 Alternating Current

Question. 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…

NCERT Class 12 Physics Moving Charges and Magnetism

  Chapter Four MOVING CHARGES AND MAGNETISM 4.1 INTRODUCTION Both Electricity and Magnetism have been known for more than 2000 years. However, it was only about 200 years ago, in 1820, that it was realised that they were intimately related*. During a lecture demonstration  in…