Question

Physics: 1/

A/

Select all correct statements about northern lights:

A- charged particles like cosmic rays and the solar wind gets trapped in earth's gravitational field then colliding with earth's atmosphere close to north poles generates northern lights

B- charged particles like cosmic rays and the solar wind gets trapped in earth's magnetic field then colliding with earth's atmosphere close to north poles generates northern lights

C- charged particles like cosmic rays and the solar wind gets trapped in earth's electric field then colliding with earth's atmosphere close to north poles generates northern lights

only A is correct

only B is correct

only C is correct

Only A and B are correct

Only B and C correct

B/

For a given sinusoidal signal the oscilloscope reads the following:

Peake to peak vertical deflection factor = 8 divisions of 0.5 V/div

Period of 4 divisions of 0.01 sec/div time based division

Select all true statements about this signal:

Amplitude is 8V

Amplitude is 4V

Amplitude is 2V

Period is 0.04S

Angular frequency is 25Hz

C/

Select all true statement(s) on an electron moving inside a uniform parallel magnetic field.

electron may travel without any diflection to its original path before it enter the magnetic field

electron may travel in a circular path

electron may travel in a parabolic path path

electron may travel in a spiral path

electron may travel in a elliptic path

D/

Select all true statement(s) on a PN junction:

an electrons is a movable charge

a hole is a movable charge

positive Silicon atoms are immovable charges

positive Silicon atoms are movable charges

once the PN junction forms after stabilizing, there will an electric field formed inside the junction

Answer 1

1.

B- charged particles like cosmic rays and the solar wind gets trapped in earth's magnetic field then colliding with earth's atmosphere close to north poles generates northern lights.

2.l

Amplitude is 2V and the period is 0.04 s.

3.

The electron may travel in a circular path

The electron may travel in a spiral path.

4.

An electron is a movable charge

positive Silicon atoms are immovable charges

once the PN junction forms after stabilizing, there will an electric field formed inside the junction