How do you detect hidden cameras and microphones?
The short answer is that you will not find a well hidden camera or microphone with your mobile phone. Cameras and microphones are passive devices and do not in themselves produce anything that can be detected.If they are wireless devices with built in transmitters, a signal may be detected, but only if they are using Bluetooth or WiFi that is used by your standard phone. A signal may be present, but it’s exact location and purpose will be very hard to pinpoint with a consumer grade smartphone. This the job of specialist detectors and equipment.That being said, they are very useful in locating infrared (IR) illumination used by many surveillance systems. The imaging sensor in almost all phone cameras will detect IR and makes it easy to spot. All you need to do is scan around the area with your phone, and bingo, any IR will show up as a bright point source that your eyes cannot see. This is almost guaranteed to be part of a surveillance system.Another less nefarious use for this is to check if the batteries in a standard remote control are working. Just point the remote at the camera lens on your phone and press any of the buttons. If the remote is working, you will see the IR LED on the remote light up very brightly on the phone display. You can’t see it with your naked eyes, but the CCD sensor in the phone’s camera will show it very clearly.
How do I know the -ve & +ve terminal of a ammeter?
There is a variety of things that an rlp you know the polarity of device:If it is a single range ammeter, then there will be two terminals only. The red one is positive and black is negative.If both terminals are black, the one with 0A is positive and the range terminal is negative.If it is a multirange, then 0A is positive and range is negative.Even if you connect the terminals wrong, you will see that the deflection is going below 0A or its it is a digital one than it will show in negative.But not to worry, you can change the terminal connection again if you see above condition.
Can a gas diffuse in a gas?how about a gas in a liquid?give example?
diffusion is the movement of paricle from a region of higher conc. to a region of lower conc. therefore a gas can diffuse in a gas if either one is conc. in one point and the same goes for gas in liquid example: u can smell the fart of someone else even though he's sitting at the other end. that's because his fart diffused into the air you breathe in.
How do you find product names from a Walmart receipt?
I have answered this question here:Amit Jnagal's answer to How do I find out what the abreviation of the product is on wal mart receipts?Hope this helps!
Where can I find the RF values for thin-layer chromatography for different plants?
There is a mobile app to calculate Rf values from TLC image, HEXAI TLC.https://play.google.com/store/apps/details?id=com.hexai.hexaitlcThese are the highlights of this app:As soon you complete the sign up form. You will be redirect to home page where you can create a project by filling some information like Project Title etc.Now you can start adding TLCs to your project.To add TLC to project, First user will be have to take picture, Then set solvent's starting and end position by dragging horizontal lines.Now you chose the spot and drag the anchor point to the level of your spot, you will be getting the Rf values while dragging.User can add multiple anchors also from dropdown button.Now Click on Add icon -> Save -> fill the details of solvent -> submit.Thats all to save TLC image.Use also can share saved TLC report with your guide or friends by using any of your installed apps like gmail, WhatsApp or any other app.
How do I match the frequencies of RF transmitters and receivers?
There are many sophisticated ways to tune in frequencies of oscillators and receivers. Since this question is asked, I am assuming, you are trying to solder up a small transmitter/receiver like a DIY project of some sort. What we had done as a part of a school project:We had soldered up a transmitter, looking at the circuit from EFY. and then turned on an FM radio receiver. It was completely made from BJTs, capacitors and an inductor. Later, we moved the core of the inductor of the transmitter till we got good signal at the receiver, once that was set, we poured molten wax on the inductor to keep it stable.You can use variable capacitors also(later we got to know that transmitting in FM bands is actually illegal, but our range was too feeble to cross the classroom)