The plant require light duration more than critical day length is called as______

Nitcotiana tabacum, a Short-Day Plant, when exposed to more than critical period of light fails to flower.Explain.

Assertion : Electromagnetic waves with frequencies more than the critical frequency of ionosphere cannot be used for communication using sky wave propagation. Reason : The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency .

If the light was incident on the interface at an angle greater than critical angle which phenomenon occurs?

The perimeter of rectangle is 40 cm. The length of rectangle is 2 cm more than twice its breadth. Find the length and the breadth of the rectangle.

Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before germination. The later phenomena is called as dormancy. Give the.reasons for seed dormancy andsome methods to break it.

When a surface is irradiated with light of wavelength 4950 overset(@)(A) ,a photocurrent appears which vanishes if a retarding potential greater than 0.6 V is applied across the phototube.When different source of light is used,it is found that the critical retarding potential is changed to 1.1 V.Find the work function of the emitting surface and the wavelength of the second source

If the light was incident on the interface at an angle greater than critical angel what occurs?

When alkanes having more than five carbon atoms get cyclised to benzene and its homologues then the reaction is called _____.

For short day plants, the critical period is.......

Assertion: in optical fibre, the diameter of the core is kept small. Reason: This smaller diameter fo the fibre should have incident angle more than the critical angle required for total internal reflection.