Physics Ncert Solutions Class 12th

A system consists of two types of gas molecules A and B having same number density 2*10²⁵ / m³. The diameter of A and B are 10 Å and 5 Å respectively. They suffer collision at room temperature. The ratio of average distance covered by the molecule A to that of B between two successive collision is __________ x10⁻².

A message single of frequency 20 kHz and peak voltage of 20 volt is used to modulate a carrier wave of frequency 1 MHz and peak voltage of 20 volt. The modulation index will be __________.

A radioactive sample has an average life of 30ms and is decaying. A capacitor of capacitance 200 µF is first charged and later connected with resistor 'R'. If the ratio of charge on capacitor to the activity of radioactive sample is fixed with respect to time then the value of 'R' should be _______ Ω.

The amplitude of upper and lower side bands of A.M. wave where a carrier signal with frequency 11.21 MHz, peak voltage 15 V is amplitude modulate by a 7.7 kHz sine wave of 5 V amplitude are (a/10) V and ( b/10 ) V respectively. Then the value of a/b is _______.

A transistor is connected in common emitter circuit configuration, then collector supply voltage is 10 V and the voltage drop across a resistor of 1000Ω in the collector is 0.6 V. If the current gain factor (β) is 24, then the base current is _______ µA. (Round off to the Nearest Integer)

Identify the logic operation carried out.
(The diagram shows a logic circuit with two inputs A and B. Both A and B are inputs to a NAND gate. The output of this NAND gate is then fed into both inputs of a second NAND gate, which produces the final output Y.)

In Amplitude Modulation, the message signal V?(t) = 10 sin(2π * 10?t) volts and carrier signal V?(t) = 20 sin(2π * 10?t) volts. The modulated signal now contains the message signal with lower side band and upper side band frequency, therefore the bandwidth of modulated signal is α kHz. The value of α is:

Two ideal electric dipoles A and B, having their dipole moment p₁ and p₂ respectively are placed on a plane with their centres at O as shown in the figure. At point C on the axis of dipole A, the resultant electric field is making an angle of 37° with the axis. The ratio of the dipole moment of A and B, p₁ and p₂ , is:
(take sin 37° = 3/5)

In the Young's double slit experiment, the distance between the slits varies in time as d(t) = d? + a? sin(ωt); where d?, ω and a? are constants. The difference between the largest fringe width and the smallest fringe width obtained over time is given as :

An audio signal V_m = 20 sin 2p(1500t) amplitude modulates a carrier

V_C = 80 sin 2p (100,000t)( The value of percent modulation is______________.