questions regarding CRO (physics)

anpanman SG

Let's say the x-plate and y-plate of the CRO is switched on. A DC is supplied to it.

May I know what you will see on the display?

My tutor says for CRO, you WILL ALWAYS see only a dot across the screen. But according to the notes provided by my teacher, you only see a dot when the time base is not switched on but you see a horizontal line when time base is switched on. Can someone further explain?

Secondly,

when determining the brightless of a light bulb across a circuit,

do you look at the

1. voltage across bulb OR

2. current across bulb OR

3. energy dissipated by bulb

thanks for answering my queries.

yiha093 SG

Let's say the x-plate and y-plate of the CRO is switched on. A DC is supplied to it.

May I know what you will see on the display?

Secondly,

when determining the brightless of a light bulb across a circuit,

do you look at the

1. voltage across bulb OR

2. current across bulb OR

3. energy dissipated by bulb

thanks for answering my queries.

brightness u look at resistance of bulb xD

ok la. i think , another 1 is power(energy disspiated by bulb). cause its amount of work done per second !

yiha093 SG

for CRO look at TB, theres a section which shows u various types of current and situations ( the waveform formed) mai lazy.

wxboi SG

i think for the CRO you'll see a straight line above the rest position

for the bulb i'll see energy dissipated but anyone wanna confirm with me cos im also taking the mcq exam tomorrow.

qdtimes2 SG

the time base allows electrons to sweep horizontally on the screen. in a d.c. circuit, the straight produced may not necessarily be above the rest position. When it's below the rest position, it means that the dry cells are placed wrongly.

and i thought all of the 3 factors affect the brightness of the bulbs...

V = E/Q and V = R x I

so normally i see the voltage across the bulb