Question

The horizontal deflection plates in a CRT are 20 mm long and 5 mm apart. The centre of the plate is 20 cm from the screen. Accelerating voltage is 2500 V. Then the deflection sensitivity is ______mm/V.
(Answer upto two decimal places)

• A. 1.6
• B. 0.16
• C. 0.6
• D. 16

Answer 1

The correct option is B 0.16

Length of plates,
$l=20mm=0.02m$

Distance between plates,
$d=5mm=0.005m$

The distance between the screen and centre of plates,
S = 0.2 m

Accelerating voltage,
$V_a=2500V$

Deflection sensitivity

$=\frac{lS}{2d{V}_a}$

$=\frac{0.02\times 0.2}{2\times 0.005\times 2500}=0.16mm/V$