Electric Charges and Fields — Physics STD 12 Science — Question

If the frequency of EM radiations is halved then the energy of EM radiation will become:

The two ends of a spring are displaced along the length of the spring. All displacement have equal magnitudes. In which case or cases the tension or compression in the spring will have a maximum magnitude?

1. The right end is displaced towards right and the left end towards left.
2. Both ends are displaced towards right.
3. Both ends are displaced towards left.
4. The right end is displaced towards left and the left end towards right.

A man suffering from myopia can read a book placed at 10 cm distance. For reading the book at a distance of 60 cm with relaxed vision, focal length of the lens required will be(a) 45 cm  (b) – 20 cm  (c) – 12 cm  (d) 30 cm  

A ferromagnetic material is heated above its curie temperature. Which one is a correct statement(a) Ferromagnetic domains are perfectly arranged(b) Ferromagnetic domains becomes random(c) Ferromagnetic domains are not influenced(d) Ferromagnetic material changes itself into diamagnetic material

A 50 mH coil carries a current of 2 ampere. The energy stored in joules is(a) 1 (b) 0.1(c) 0.05(d) 0.5

Through which mode of propagation, the radio waves can be sent from one place to another (a) Ground wave propagation (b) Sky wave propagation(c) Space wave propagation(d) All of them

Young’s double slit experiment is performed with light of wavelength 550 nm. The separation between the slits is 1.10 mm and screen is placed at distance of 1 m. What is the distance between the consecutive bright or dark fringes (a) 1.5 mm(b) 1.0 mm(c) 0.5 mm(d) None of these

A listener is at rest with respect to the source of sound. A wind starts blowing along the line joining the source and the observer. Which of the following quantities do not change?

1. Frequency.
2. Velocity of sound.
3. Wavelength.
4. Time period.