Calculate the maximum velocity of the beam of electrons in a CRT having a cathode and anode voltage of 182 V. Assume that the electrons leave the cathode with zero velocity. (Charge of electron = 1.6 × 10-19 C and mass of electron = 9.1 × 10-31 kg)
8 × 106 m/s
To calculate the maximum velocity of the beam of electrons in a CRT, we need to use the energy conservation equation for electrons accelerated through a potential difference. The kinetic energy gained by the electron is equal to the work done on it by the electric field, which can be expressed as follows:
K.E. = qV
Where:
- K.E. is the kinetic energy of the electron,
- q is the charge of the electron = 1.6 × 10-19 C,
- V is the potential difference = 182 V.
As the electrons are initially at rest, their initial kinetic energy is zero. Hence, all the energy transferred to them is converted into kinetic energy:
K.E. = 1/2 mv2
Where:
- m is the mass of the electron = 9.1 × 10-31 kg,
- v is the velocity of the electron.
Equating the kinetic energy with the work done:
1/2 mv2 = qV
Rearranging for v:
v = sqrt((2*q*V)/m)
Substitute the known values into the equation:
v = sqrt((2 * 1.6 × 10-19 C * 182 V) / 9.1 × 10-31 kg)
Calculate the result:
v = sqrt((5.824 × 10-17 J) / 9.1 × 10-31 kg)
v ≈ sqrt(6.4 × 1013)
v ≈ 8 × 106 m/s
Thus, the maximum velocity of the beam of electrons is 8 × 106 m/s.
Important Questions from Cathode Ray Oscilloscope
The function of a trigger level knob on a CRO is:
Aquadag coating is most commonly used in CROs to:
CRO stands for:
Which of the following expression is the correct formulae for the deflection sensitivity ‘S’ of a CRT, if
D = deflection on the fluorescent screen
L = distance from the center of the deflection plates to the screen
Ld = effective length of the deflection plates
d = distances between the deflection plates
Ed = Potential between deflecting plates
Ea = accelerating voltageTrigger pulses in CRO are used -
