The minimum frequency v of continuous X-rays is related to the applied potential difference V as
|
(a) v ∝ |
(b) v ∝ v |
(c) v ∝ |
(d) v ∝ |
The minimum frequency v of continuous X-rays is related to the applied potential difference V as
|
(a) v ∝ |
(b) v ∝ v |
(c) v ∝ |
(d) v ∝ |
(b) v ∝ v
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
The emf of a thermocouple, one junction of which is kept at 0℃, is given by
the Peltier co-efficient will be
|
(a) (t + 273) (a + 2bt) |
(b) (t + 273) (a – 2bt) |
|
(c) (t – 273) (a- 2bt) |
(d) (t – 273) (a – 2bt) |
Focal length of a convex lens of refractive index 1.5 is 2 cm. Focal length of lens when immersed in a liquid of refractive index of 1.25 will be
|
(a) 10 cm |
(b) 2.5 cm |
(c) 5 cm |
(d) 7.5 cm |
A 2 volt battery, a 15 Ω resistor and a potentiometer of 100 cm length, all are connected in series. If the resistance of potentiometer wire is 5 Ω, then the potential gradient of the potentiometer wire is
|
(a) 0.005 V/cm |
(b) 0.05 V/cm |
(c) 0.02 V/cm |
(d) 0.2 V/cm |
When the electrical conductivity of a semi- conductor is due to the breaking of its covalent bonds, then the semiconductor is said to be
|
(a) Donar |
(b) Acceptor |
(c) Intrinsic |
(d) Extrinsic |
In a lossless transformer an alternating current of 2 amp is flowing in the primary coil. The number of turns in the primary and secondary coils are 100 and 20 respectively. The value of the current in the secondary coil is
|
(a) 0.08 A |
(b) 0.4 A |
(c) 5 A |
(d) 10 A |
Two long conductors, separated by a distance d carry current I1 and I2 in the same direction. They exert a force F on each other. Now the current in one of them is increased to two times and its directions is reversed. The distance is also increased to 3d. The new value of the force between them is
|
(a) –2F |
(b) F/3 |
(c) 2F/3 |
(d) – F/3 |
In determining the temperature of a distant star, one makes use of
|
(a) Kirchhoff's law |
(b) Stefan's law |
|
(c) Wien's displacement law |
(d) None of these |