What is the need for watering a newly constructed wall?Manoj bonam, Rajahmundry, Andhra PradeshUnlike LCD TVs , why do CRT TVs show different colours on their screen when a magnet is kept near them?A. Saravanan, ChennaiHow does an overdose of sleeping tablets cause death?K. Ragunathan, Coimbatore, Tamil Nadu Why does the human body not feel an electric shock at low voltages such as 12 volts?S. Yuvaraj, Coimbatore, Tamil NaduReaders can send questions/answers on science and technology for the Question Corner along with their names and address to the following email id:questioncorner@thehindu.co.in or to The Editor, The Hindu (Science and Technology), 859-860, Anna Salai, Chennai 600 002.