Should I try with increasing the line frequency? such as 10KHz or 100KHz? Because generating at MHz range will not be easy. Also space is a matter for presentation.
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The effects you wish to demonstrate only occur over very long power transmission line distances, hundreds or thousands of Km.
To shrink that down to work bench size needs a frequency increase of the same order.
Even at 100 Khz one full wavelength is still 3 Km
At 100 Mhz it is only 3 metres.
A frequency a bit lower tha 100 Mhz would be workable.
The ideal thing would be a small radio transmitter with a few watts of output, and a light bulb indicator.
Even right at the back of the class, the simplicity of the setup would make for a pretty dramatic and convincing demonstration.
I believe there are 16,000 licensed Ham Radio operators in India. See if you can find a local club or contact.
Someone there might be able to help you to assemble some suitable equipment.
https://www.hamradio.in/index.php?sid=51c17b8a0a6c8cbfefb33e9ee2b25896
There is also a Forum at that site.
That may be your best bet.