What physical quantity is the same for X-rays of wavelength \(10^{−10} m\), red light of wavelength \(6800 Å\) and radio waves of wavelength \(500\ m\)?
What physical quantity is the same for X-rays of wavelength \(10^{−10} m\), red light of wavelength \(6800 Å\) and radio waves of wavelength \(500\ m\)?
Solution and Explanation
The speed of light \((3 \times 10^8\ m/s)\) in a vacuum is the same for all wavelengths. It is independent of the wavelength in the vacuum.
Top Questions on Electromagnetic Waves
- How is an electromagnetic wave produced?
- CBSE CLASS XII - 2025
- Physics
- Electromagnetic Waves
- An electromagnetic wave is travelling in vertically upward direction. At an instant, its electric field vector points in west direction. In which direction does the magnetic field vector point at that instant?
- CBSE CLASS XII - 2025
- Physics
- Electromagnetic Waves
- Estimate the ratio of shortest wavelength of radio waves to the longest wavelength of gamma waves.
- CBSE CLASS XII - 2025
- Physics
- Electromagnetic Waves
- X-rays are more harmful to human beings than ultraviolet radiations because X-rays:
- CBSE CLASS XII - 2025
- Physics
- Electromagnetic Waves
- The electric field in a plane electromagnetic wave is given by \(E_z = 60 \cos(5x + 1.5 \times 10^{10} t)\) V/m. Then expression for the corresponding magnetic field (\(B_y\)) is (here subscripts denote the direction of the field) is:
- NEET (UG) - 2025
- Physics
- Electromagnetic Waves
Questions Asked in CBSE CLASS XII exam
- Determine those values of $x$ for which $f(x) = \frac{2}{x} - 5$, $x \ne 0$ is increasing or decreasing.
- CBSE CLASS XII - 2025
- Functions
- Agro-startups and rural enterprises are becoming increasingly vital for rural development in India. They address the critical challenges faced by rural sector in India. These ventures bring in technological innovations such as precision farming, IT-based monitoring system and data-driven decision making tools that enhance productivity and resource efficiency. By streamlining supply chains and creating direct market linkages, they ensure better pricing for farmers and reduce dependency on traditional intermediaries. Such enterprises contribute actively to employment generation in the rural areas. The government has demonstrated a continuous policy and financial support for agri-startups and entrepreneurs through various programs like RKVY-RAFTAAR, the Agri- infrastructure fund and Agri-SURE.
On the basis of given text and common understanding, answer the following questions:- CBSE CLASS XII - 2025
- Rural Development
Read the following text carefully:
Union Food and Consumer Affairs Minister said that the Central Government has taken many proactive steps in the past few years to control retail prices of food items. He said that the government aims to keep inflation under control without compromising the country’s economic growth. Retail inflation inched up to a three-month high of 5.55% in November 2023 driven by higher food prices. Inflation has been declining since August 2023, when it touched 6.83%. 140 new price monitoring centres had been set up by the Central Government to keep a close watch on wholesale and retail prices of essential commodities. The Government has banned the export of many food items like wheat, broken rice, non-basmati white rice, onions etc. It has also reduced import duties on edible oils and pulses to boost domestic supply and control price rise. On the basis of the given text and common understanding,
answer the following questions:- CBSE CLASS XII - 2025
- Government Budget and the Economy
- Distinguish between Physical Capital and Human Capital.
- CBSE CLASS XII - 2025
- Human Capital Formation
- “In the recent Budget the Government allocated funds for construction of new metro lines in smart cities to improve public transportation and reduce pollution.”
Identify the nature of government expenditure \& its objective.- CBSE CLASS XII - 2025
- Government Budget and the Economy
Notes on Electromagnetic Waves
Concepts Used:
Electromagnetic Spectrum
The term used by scientists to describe the entire range of light that exists is the electrostatic spectrum. Light is a wave of alternating electric and magnetic fields. The propagation of light doesn't vary from waves crossing an ocean. Like any other wave, light also has a few fundamental properties that describe it. One is its frequency. The frequency is measured in Hz, which counts the number of waves that pass by a point in one second.
The electromagnetic waves that your eyes detect are visible light and oscillate between 400 and 790 terahertz (THz). That’s several hundred trillion times a second.