Top 10 Tech Myths

1. Switching off a PC or removing a USB stick incorrectly can damage the device

It won’t physically damage the hardware, however there’s a small risk of damage to your data. Most obviously, any unsaved work in open applications will be lost. But it’s also possible to corrupt the filing system on the hard disk, which keeps track of where all the files are.

This can usually be repaired automatically by the system, but it can be quite a long process so it just makes your PC or console much slower to start next time. For USB disks and memory sticks the same thing applies. If you don’t eject the device before you physically unplug it, you are running a small but real risk of data corruption, so the moral of the story is: be patient with your computing devices on shut down. TRUSTED

2. You should never use your mobile at a petrol station

The fear is that the electromagnetic (EM) radiation from a mobile phone could impart enough energy to ignite petrol vapour directly or that it could induce currents in nearby metal objects and trigger a spark with the same effect. But a study found that in 243 petrol station fires around the world between 1994 and 2005, none were caused by mobile phones. In fact, there isn’t a single confirmed case of this ever happening. Even a lit cigarette isn’t hot enough to ignite petrol vapour. You need a naked flame or a spark, and mobile phones have low-voltage batteries that aren’t capable of producing either.

Petrol station fires are very rare and nearly all are caused by sparks from static electricity igniting petrol vapour. This requires just the right mix of air and vapour, which is much less likely to occur now that pumps have vapour-recovery systems installed. BUSTED

3. Fibre-optic broadband works faster

The tech certainly allows for much faster data rates, but how much of that you actually see depends on your ISP. A study by Ofcom in 2010 found average broadband speeds in the UK were around 6.2Mbps, compared with the average advertised theoretical speed of 13.8Mbps. However, fibre-optic broadband does seem to come closer to its advertised speed than ordinary ADSL broadband – eg Virgin Media customers on ‘up to 50Mbps’ packages managed an average of 43.9-47.2Mbps. TRUSTED

4. Airport security machines destroy electronic devices

Conveyor belt luggage scanners use X-rays, millimetre waves or submillimetre ‘T-waves’. These are all forms of electromagnetic radiation but they are low intensity and the radiation frequency is non-ionising, so it won’t affect electronics/memory cards. According to the US Transportation Security Administration, the X-ray dose from a scanner is much less than you would normally receive due to the slightly higher background radiation while flying. The metal detectors you walk through use powerful magnets though and could pose a risk to the hard disks in laptops and some video cameras. But these items have to be scanned on the conveyor belt anyway. BUSTED

5. The most economical speed at which to drive your car is 55mph

Car engines are actually most efficient at a particular number of revs, rather than road speed. For most cars this is around 2,000 rpm. As you accelerate, the revs rise above this and you change up a gear to maintain efficiency. As soon as you reach fifth gear, with the revs around 2,000, you are at the most efficient speed. That’s just 56-74 kilometres (35-45 miles) per hour for the majority of cars. 89 kilometres (55 miles) per hour is often quoted as a more economical compromise to encourage drivers to slow down from 113 kilometres (70 miles) per hour. It doesn’t mean that 55 is the optimum speed. BUSTED

6. If you touch a light switch with wet hands you will be electrocuted

This one’s a bit of a grey area because while it might be theoretically possible this could happen, it’s very unlikely. Your hands would have to be wet enough for water to drip past the rocker to the live wires behind it and complete a circuit with your finger in the time it takes for you to flick the switch. This would give you an electric shock but probably only at your fingertips. To electrocute you, on the other hand, the current would have to flow through your body and stop your heart. That’s much more likely if your whole body is wet, which is why bathroom light switches tend to use pull cords to keep your wet hands away from the wiring, just to be on the safe side. TRUSTED

7. More megapixels make for better photos

When digital cameras first appeared, the resolution of the sensor was low enough that you could easily make out the individual pixels when they were printed out. But camera resolutions very quickly improved to the point where individual pixels were imperceptible. For instance, for 6×4 prints you only need a two-megapixel camera to be able to print at the same quality as the photos in this article. And the most you will ever need is seven megapixels. This is enough to print an A3 page at article resolution and, if you print out any larger than that, you would need to stand farther back to look at it, so the effective resolution remains the same. Once you hit this megapixel threshold, there are three main factors that affect the quality of your snaps: the skill of the photographer, the quality of the camera lens and the size of the CCD sensor in the camera. The physical size of the CCD sensor matters because it increases the amount of light gathered, which reduces image noise and increases depth of field. BUSTED

8. Using a phone during a flight can affect the navigation equipment on a plane

There are anecdotal reports of interference from various electronic devices (including DVD players, which are currently allowed) and some simulation studies suggest that interference is theoretically possible. Airlines continue to enforce a no-phones policy using the same precautionary principle adopted by petrol stations. However, a 2011 poll found that three per cent of British holidaymakers had forgotten to turn off their mobile phone when they flew. That would mean almost 6.5 million switched-on phones flew that year, suggesting the risk is – at worst – very small. BUSTED

9. Electric cars are 100% green

Fully electric cars use batteries to power electric motors. There’s no internal combustion engine, so they don’t emit greenhouse gases or other forms of air pollution. But the batteries still have to be charged by plugging them into the electricity grid and the power that this uses has to be generated somewhere. Electric cars also create more pollution during manufacture than petrol cars, particularly the batteries. BUSTED

10. PC power is still doubling every two years

Gordon Moore, who co-founded technology giant Intel, predicted back in 1975 that the number of transistors on a computer chip would double every two years. This is referred to as Moore’s Law, but there’s nothing inevitable about it. The semiconductor industry has been able to maintain this trend only by spending more and more on research and development. In ten years or so, miniaturisation will bottom out at atomic scale, but bigger chips and new tech could still allow the power of each chip to increase. For now at least, Moore’s Law still holds. TRUSTED