### Physics - electrons and Protons

#### Question - 1

Strong argument for the particle nature of cathode rays is to

• A Produce fluorescence
• B travel throught vacuum
• C get deflection by electric and magnetic fields
• D cast shadow

#### Question - 2

An electron is projected pointing in the same direction of electric and magnetic fields.  Then

• A the electron turns to right
• B the electron turns to right
• C the electron continues to move in the same direction but with less velocity
• D the electron continues to move in the same direction but with increased velocity

#### Question - 3

Cathode rays are projected pointing normal to the direction of electric field.  Their path is

• A straight line
• B ellipse
• C circle
• D parabola

#### Question - 4

Neon lamps work in the region of

• A cathode glow
• B negative glow
• C positive column
• D Crooke's dark space

#### Question - 5

The specific charge of electron is

• A $1.6\times10^{-19}C$
• B $9.1 \times10^{-31}kg$
• C $1.76\times10^{11}C kg^{-1}$
• D $5.7\times10^{-12}kg C^{-1}$

#### Question - 6

Gases begin to conduct electricity at low pressure because

• A The electrons in atoms can move freely at-low pressure
• B Atoms break up into electrons and protons
• C Colliding electrons can acquire higher kinetic energy due to increased mean free path causing ionisation of atoms
• D At low pressure gas turn into plasma

#### Question - 7

Proton is 1840 times heavier than an electron.  The ratio of specific charge of $\alpha$-particle to that of electron is

• A 1840
• B $(1840)^{-1}$
• C $(3680)^{-1}$
• D 3680

#### Question - 8

Energy of an electron can be increased by

• A making them fall from a great height
• B moving them through an electric potential
• C passing them through lead block
• D passing them through high magnetic field

#### Question - 9

The specific charge of a proton is 9.6$\times 10^{7}C \ kg^{-1}$.  That for $\alpha$ particle will be

• A 9.6$\times 10^{7}C \ kg^{-1}$
• B 4.8$\times 10^{7}C \ kg^{-1}$
• C 2.4$\times 10^{7}C \ kg^{-1}$
• D 38.4$\times 10^{7}C \ kg^{-1}$

#### Question - 10

A proton moving with velocity $\vartheta$ is acted upon by electric field E and magnetic filed B.  The proton will move undeflected if

• A E is perpendicular to B
• B E is parallel to $\vartheta$ and perpendicular to B
• C E, B and $\vartheta$ are mutually perpendicular and $\vartheta ={E\over B}$
• D E and B both are parallel to $\vartheta$.