Four resistances of 100 ohm each are connected in the form of a square. Then the effective resistance along the diagonal points is:

(1) 150 ohms
(2) 100 ohms
(3) 400 ohms
(4) 200 ohms

 A conducting loop lies in the plane of this page and carries a clockwise induced current. Which of the following statements could be true?

(1) A constant external magnetic field is directed into the page.

(2) A constant external magnetic field is directed out of the page.

(3) An increasing external magnetic field is directed into the page.

(4) A decreasing external magnetic field is directed into the page.

'n' electrons flow through a cross-section of a conductor in time t. If charge on an electron is 'e', then the current in the conductor would be

1) $$\displaystyle \frac{ne}{t}$$
2) $$\displaystyle \frac{ne^2}{t}$$
3) $$\displaystyle \frac{e}{t}$$
4) $$\displaystyle \frac{n}{et}$$

The resistance in the four arms of a Wheatstone network in cyclic order are 5Ω,2Ω,6Ω and 15Ω. If a current of 2.8A enters the junction of 5Ω and 15Ω, then the current through 2Ω resistor is

1) 1.5 A
2) 2.8 A
3) 0.7 A
4) 2.1 A

 A photon or quantum of light has wavelength ë and frequency f. Its energy is proportional to

1) 1/ë    2) f^1/2     3) the light intensity     4) cë

The rms value of the electric field of the light from the sun is 720N/C The total energy density of the electromagnetic wave is

1) 6.37×10⁻⁹Jm⁻³
2) 81.35×10⁻¹²Jm⁻³
3) 3.5×10⁻³Jm⁻³
4) 4.58×10⁻⁶Jm⁻³

In which of the following heat loss is primarily not due to convection.

In a medium where the velocity of sound is 45 m/s a source of frequency 150Hz will produce waves with a wavelength of
 
 (1) 0.3 m
 (2) 0.5 m
 (3) 3.0 m
 (4) 5.0 m

If the value of gravitational acceleration at a height h above the Earth's surface is the same as that at a depth d below the Earth's surface (with both h and d small compared to the Earth's radius R), then
 
 1) h = 2 d
 2) h = d
 3) h = d2 / R
 4) h = d / 2

The numerical aperture of objective of a microscope is 0.12. The limit of resolution, when light of wavelength 6000?A is used to view an object is:

1) 0.25×10⁻⁷m
2) 2.5×10⁻⁷m
3) 250×10⁻⁷m
4) 25×10⁻⁷m