Nuclei — Physics STD 12 Science — Question

The cold junction of a thermocouple is maintained at 10ºC. No thermo e.m.f. is developed when the hot junction is maintained at 530ºC. The neutral temperature is:

A prism having an apex angle 4^o and refraction index 1.5 is located in front of a vertical plane mirror as shown in figure. Through what total angle is the ray deviated after reflection from the mirror

(a) 176o

(b) 4o

(c) 178o

(d) 2o

If Fresnel’s biprism experiment as held in water inspite of air, then what will be the effect on fringe width

(a) Decrease

(b) Increase

(c) No effect

(d) None of these

Two particles X and Y having equal charge, after being accelerated through the same potential difference enter a region of uniform magnetic field and describe circular paths of radii R₁ and R₂ respectively. The ratio of the mass of X to that of Y is:

Which of the following element has maximum binding energy per nucleon?

Assertion   :  The magnetic filed at the ends of a very long current carrying solenoid is half of that at the center.

Reason      : If the solenoid is sufficiently long, the field within it is uniform.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

With the rise in temperature, the  dielectric constant K of a liquid

(a) Increases	(b) Decreases
(c) Remains unchanged	(d) Charges erratically

In a transformer, number of turns in the primary are 140 and that in the secondary are 280. If current in primary is 4A then that in the secondary is

(a) 4 A

(b) 2 A

(c) 6 A

(d) 10 A

In an FM system a 7 kHz signal modulates 108 MHz carrier so that frequency deviation is 50 kHz. The carrier swing is

(a) 7.143

(b) 8

(c) 0.71

(d) 350