Question

Which one is correct relation for thermionic emission

(a)  

(b)  

(c)  

(d)  

Answer

(b)  

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The resistance of a wire of iron is 10 ohms and temp. coefficient of resistivity is  5 . At  20 it carries 30 milliamperes of current. Keeping constant potential difference between its ends, the temperature of the wire is raised to 120. The current in milliamperes that flows in the wire is

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The mass of an atomic nucleus is less than the sum of the masses of its constituents. This mass defect is converted into?

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In which radioactive disintegration, neutron dissociates into proton and electron

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Consider a capacitor-charging circuit. Let Q1 be the charge given to the capacitor in a time interval of 10ms and Q2 be the charge given in the next time interval of 10ms. Let 10mC charge be deposited in time interval t1 and another 10mC charge be deposited in the next time interval t2.
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  3. Q1 < Q2, t1 > t2
  4. Q1 < Q2, t1 < t2
According to the electromagnetic wave theory, light consists of electric and magnetic fields which are_____________.