Recent content by T7

I would apply a similar sort of working to the second part. I don't see how it can be done without more information.

Yup. I think I've just realized what I was doing wrong as far as part a is concerned. Let Pa denote average power Let Pp denote power of one pulse Let Ep denote energy of one pulse Let t denote time of one pulse If Pa = 5W, and f = 100Hz, then Ep x 100 = 5 => Ep = 0.05 Pp = Ep / t = 0.05 /...

Hi, a. A free-running, flashlamp-pumped Nd:YAG laser produced pulses having a duration of 500 microseconds at a repetition frequency of l00Hz. Deduce the pulse power in this type of operation if the average power of the laser is 5W. (100W) b. This laser is then Q-switched and the average...

Ah, now I see. Thanks folks. :smile:

Hi, I have an optics Q here I'm not quite sure about:- a.) An astronomers uses a single thin lens of focal length 0.5m to form a sharp image of the sun on a white screen. If the angular width of the sun is 0.5 degrees, what is the diameter of the sun's image. b.) At night the astronomer...

Cheers scholzie.

Hi, I appreciate that we can calculate the x-coordinate of the centre of mass of a system of bodies like this: x = (m_{1}x_{1} + m_{2}x_{2} + m_{3}x_{3} + ... + m_{n}x_{n}) / M where M is the total mass. This could be rewritten as x = \frac {1} {M} \sum_{i=1}^n m_{i}x_{i} My next step...

Thanks mezarashi.

Hi, I have a few questions about Sonometers which I've attempted to think through - though I may be missing something. Perhaps someone can fill in any gaps for me? If I was to be asked why only 'discrete modes' of vibration can exist for a sonometer, is it enough merely to talk about the...

Yep. Thanks. :)

Hi, Here's the question: a) There is a radio telescope that is 1000 feet in diameter. It is claimed that it can detect a signal that lays down on the entire surface of the Earth a power of only one picowatt. What power would be incident on the antenna in this case? It seems to me that...

Hi, Here's the question: "A car battery has an e.m.f. of 12V and an internal resistance of 0.04 ohms. The starter motor draws a current of 100A. a.) What is the terminal p.d. of the battery when the starter motor is in operation? b.) If the headlamps are rated at 12V, 36W, what is their...

Doesn't it depend on which side the current is going through (ie. which sides make up the area)?

Hi, Part of a question I am working on asks me to "calculate the resistance of 1cm^3 of copper in the form of a thin sheet 0.5mm thick (between the faces of the sheet), given a resistivity of 1.69x10^-8 Ohm metres". Given that p = RA/L, it is clear that R = pL/A = 1.69x10^-8 x L/A. So far...

Hi, I am trying to prove algebraically that light cannot pass across the corner of a right-angled block of glass of refractive index n=1.5. Would someone be willing to let me know whether the method I have used below is valid or not? 'i1' denotes the angle of incidence that the light ray...