The depth of penetration of electromagnetic waves in a medium having conductivity σ at a frequency of 2 MHz is 12.5 cm. The depth of penetration at a frequency of 8 MHz in the same medium will be:

The Dandi March, also known as the Salt Satyagraha, was led by which influential leader?

Which act formally granted independence to India, marking the end of British rule?

Who was the key figure in establishing the Indian National Congress?