Practice MCQ Questions and answers on Physics-GK

X-rays are part of the electromagnetic spectrum, an ionizing radiation with wavelengths shorter than ultraviolet light. X-ray tubes evolved from experimental Crookes tubes with which X-rays were first discovered in the late 19th century, and the availability of this controllable source of X-rays created the field of radiography, the imaging of opaque objects with penetrating radiation.

Wilhelm Roentgen, Professor of Physics in Wurzburg, Bavaria, discovered X-rays in 1895 accidentally while testing whether cathode rays could pass through glass.

The ozone layer is a layer in Earth’s atmosphere containing relatively high concentrations of ozone (O3) which absorbs 97–99% of the Sun’s medium-frequency ultraviolet light.

Ultrasound or ultrasonography is a medical imaging technique that uses high frequency sound waves and their echoes. The technique is similar to the echolocation used by bats, whales and dolphins, as well as SONAR used by submarines.

All electromagnetic waves used are infrared.

Electromagnetic waves do not show interference and diffraction.

Red has the longest wavelength.

Infrared imaging is used extensively for military and civilian purposes. Military applications include target acquisition, surveillance, night vision, homing and tracking. Non-military uses include thermal efficiency analysis, environmental monitoring, industrial facility inspections, remote temperature sensing, short-ranged wireless communication, spectro-scopy, and weather forecasting. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe. There are two main types of remote sensing: passive remote sensing and active remote sensing. Reflected sunlight is the most common source of radiation measured by passive sensors. Examples of passive remote sensors include film photography, infrared, charge-coupled devices, and radiometers.

X - rays, infrared, visible, microwave

Gamma rays has the shortest wavelength.