Which one is correct relation for thermionic emission
|
(a) |
(b) |
(c) |
(d) |
Which one is correct relation for thermionic emission
|
(a) |
(b) |
(c) |
(d) |
(b)
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Two coils A and B having turns 300 and 600 respectively are placed near each other, on passing a current of 3.0 ampere in A, the flux linked with A is 1.2
and with B it is 9.0
. The mutual inductance of the system is
|
(a) 2 × 10–5 henry |
(b) 3 × 10–5 henry |
(c) 4 × 10–5 henry |
(d) 6 × 10–5 henry |
Curies law can be written as
|
(a) x ∝ (T - |
(b) x ∝ |
(c) x ∝ |
(d) x ∝ T |
A bar magnet of magnetic moment 200 A-m2 is suspended in a magnetic field of intensity 0.25 N/A-m. The couple required to deflect it through 30o is
|
(a) 50 N-m |
(b) 25 N-m |
(c) 20 N-m |
(d) 15 N-m |
A charged particle moving in a magnetic field experiences a resultant force
|
(a) In the direction of field |
|
(b) In the direction opposite to that field |
|
(c) In the direction perpendicular to both the field and its velocity |
|
(d) None of the above |
A railway compartment is lit up by thirteen lamps each taking 2.1 amp at 15 volts. The heat generated per second in each lamp will be
|
(a) 4.35 cal |
(b) 5.73 cal |
(c) 7.5 cal |
(d) 2.5 cal |
In a hydrogen discharge tube it is observed that through a given cross-section 3.13 electrons are moving from right to left and 3.12
protons are moving from left to right. What is the electric current in the discharge tube and what is its direction
|
(a) 1 mA towards right |
(b) 1mA towards left |
|
(c) 2mA towards left |
(d) 2mA towards right |