Wilhelm Rontgen showed that when electrons strike a material in the cathode ray tube, some rays are originated that can cause fluorescence in the fluorescent material placed outside the cathode ray tubes. He named these rays as X-rays as these were not deflected by electric and magnetic field. X-rays are used as a diagnostic tool in the treatment of disease and bone fracture. An intelligence officer, John catched a smuggler by using this X-ray machine. He was trying to smuggle the drugs while travelling abroad.
(a) Why are X-rays used at airport to screen luggage?
(b) Why are only X-ray choosed to screen the luggage?
(c) What values are not possessed by John? What measures should be taken to prevent this?

Sheela was a student. One day, she saw that rainbow appears in the sky after raining. Another day, when she was drying her hairs in sunlight, she found the same combination of colour, by watching the sunlight through her hairs. She was very surprised but confused also. She asked about this from her science teacher who satisfied her by telling about the composition of light (white light) and its splitting into different colours when passed through different medium.
(a) Give the composition of white light?
(b) Can you guess why she saw a phenomenon similar to formation of rainbow when light passed through her hair?
(c) Applying Bohr's model when electrons in H-atom comes from n = 4 to n = 2, m calculate the wavelength of the line.
\(\left( { R }_{ H }=2.18\times { 10 }^{ -18 }J, \ h=6.63\times { 10 }^{ -34 }J \right) \).
(d) What values are associated with Sheela's teacher?