4 Feb 2015

Texas Instruments Quiz - More Questions!

Hello everybody!

So as I said in my previous post, I wanted to put up a few more questions for preparation and just for fun. These are some interesting questions which you can try.

  1. Most vehicles have an RPM meter but even when the vehicle is at idle, the RPM meter does not show zero. (But the engine is turned on). So this meter shows the RPM of what? (Try to get the specific answer)
  2. When you open a refrigerator and then close it, sometimes the fridge door get 'stuck' and needs a lot of force to open it. However if left alone for sometime, the door opens normally again. How do you explain the door getting stuck and then opening normally again sometime later?
  3. Satellites are placed in space and many of them continuously face the sun and receive heat from it. This should cause them to keep heating up until the temperature becomes very high and the satellite is damaged. But this does not happen. How / Why?
  4. Nokia posted this as a response to 'X'. ID X.
  5. There is a natural gas field in Turmekistan called the Door To Hell. Soviet engineers in 1971 found this natural gas site but the whole region collapsed into a crater. They lit the gas and expected it to burn out within a few weeks but it continues to burn till date. Even though burning the gas produces CO2 which is a greenhouse gas, it is considered to be better than letting the gas escape. Why?
  6. In a camera with an electronic flash, immediately after clicking a photo with the flash, a high-frequency whirring sound can be heard sometimes. We say that the 'flash is charging'. What exactly needs to charge? Why does it need to charge? 
  7. Related to the previous question. Explain why this sound is heard. (You might also hear it some other electronics)
  8. What purpose did screensavers serve on computer screens and TVs?
  9. There was an app called 'Bump' which allowed two people with the app to just bump their phones to share files with each other over the internet. It does not use Bluetooth or NFC. Can you explain how this worked?
  10. The picture below has many red dots. What do these represent? (Hint: Related to automobiles)
Try to answer as many as you can!


  1. Replies
    1. A few days before TI Quiz maybe? Think about them first. You can get most of them by googling later.

  2. Answers please .. 2 Days to go for quiz

  3. Answers!

    1. Its the RPM of the crankshaft of the engine. The crankshaft converts the linear motion of the pistons to circular motion.

    2. (Previous TI Question) When the door is opened, some cold air comes out and some warm air goes in. Once the door is shut, as the warm air which went in cools down, it contracts and creates a small vacuum which makes it difficult to open the door. However, since the seal of the door is not perfect, some air can enter slowly and equalize the pressure.

    3. (Previous TI Question) Even though the satellite is continuously facing the sun and absorbing heat, the satellite like any other object also radiates its heat. At a particular temperature, the rate of heat received from the sun is equal to the heat lost due to radiation and there is equilibrium. So the temperature does not heat up beyond a temperature.

    4. The picture was tweeted by Nokia when Apple launched the iPhone 5c which had a plastic body in many colours, which looked similar to Nokia's Lumia phones.

    5. Natural gas contains methane which causes a greater greenhouse effect than carbon-di-oxide. They did not want to extract the natural gas through other means as it would be too expensive.

    6. The flash of a camera works by passing a large amount of electricity through the flash tube which contains xenon gas. To provide this burst of energy, a capacitor is used to store the energy and is released in a burst. So the capacitor takes time to 'charge' from the battery. The charging circuit makes this whirring/whining noise.

    7. The whining noise is usually due to the vibration of the coils in the circuit. They vibrate due to changing magnetic fields.

    8. On CRT monitors, if the same image was displayed on the screen, the image would 'burn-in' and create a ghost image permanently on the screen. Screensavers avoided this by having continuously moving images. This does not affect most LCD displays of today. However it does affect OLED displays.

    9. (Interesting question) Bump was purchased by Google and the app was shut down.
    The app used the sensors on the phones like accelerometers and GPS and uploaded it to the servers. The algorithm then figures out which two phones felt a similar bump and then transfers the data between the two phones.

    10. These spots are the places where Tesla has charging stations for its electric cars.

    All the best!

  4. Thank you very much Abhishek Krishna