Work function of oxide coated cathode is much lower than that of tungsten cathod

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Question
Work function of oxide coated cathode is much lower than that of tungsten cathode.
Options
A. True
B. False

Correct Answer

True

Explanation

Therefore emission current from oxide coated cathode is more.

More questions

1. Assertion (A): Slotted line is frequently used for microwave measurements.
Reason (R): The unknown impedance is mounted at the end of slotted line.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

2. Match the following:

	List I		List II
A.	Digital counter	1.	Measurement of harmonics
B.	Schering Bridge	2.	Measurement of frequency
C.	Meggar	3.	Measurement of loss angle of dielectric
D.	Spectrum analyser	4.	Measurement of insulation resistance

Options
A. A-1, B-2, C-3, D-4
B. A-4, B-3, C-2, D-1
C. A-2, B-3, C-4, D-1
D. A-4, B-1, C-3, D-2

3.

List I List II (Value of tan^-1 )

A. 1. 90�

B. 2. 0�

C. 3. 50�
Options
A. A-1, B-2, C-3
B. A-2, B-1, C-3
C. A-3, B-1, C-2
D. A-3, B-2, C-1

4. Match the following:

	List I (Circuits)		List II (Output dc voltage)
A.	Single phase half wave converter	1.
B.	Fully controlled bridge converter (1 phase) with RLE load	2.
C.	3 Phase full converter	3.
D.	Single phase full wave converter (M-2) connection	4.

Options
A. A-1, B-2, C-3, D-4
B. A-4, B-3, C-1, D-2
C. A-4, B-2, C-3, D-1
D. A-1, B-2, C-4, D-3

5. Assertion (A): In a parallel plate capacitor having area of plate 1 m² and plate separation 1 m, the capacitance C and resistance R are given by C = ?₀?^'_r and R = where ? is frequency, ?_r^' and ?_r^" are real and imaginary parts of dielectric constant.
Reason (R): The imaginary part of electric constant is responsible for dielectric losses.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

6. Assertion (A): In circular waveguide the attenuation of TE₀₁ mode decreases as the operating frequency increases.
Reason (R): The wall currents in a circular waveguide in TE_Q1 mode are completely circumferential.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

7. Match the following:

	List I		List II
A.	45	1.	10110100
B.	90	2.	11010010
C.	180	3.	01011010
D.	210	4.	00101101
		5.	10101000

Options
A. A-3, B-4, C-5, D-2
B. A-4, B-3, C-5, D-2
C. A-4, B-3, C-1, D-2
D. A-3, B-4, C-2, D-1

8. Assertion (A): If an atom of polarizability a is placed in homogeneous field E, the energy stored is 0.5 aE².
Reason (R): Capacitance of an isolated conducting sphere R in vacuum is 4 p?₀ R farads.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

9. Assertion (A): PIN diode is used as a fast switch.
Reason (R): PIN diode has very high resistance when reverse biased and very low resistance when forward biased.
Options
A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. A is wrong but R is correct

10. Assertion (A): Electron concentration n, hole concentration p and charge concentration n_i are related by n_i² = np.
Reason (R): p type semiconductor is obtained by adding trivalent impurity to intrinsic semiconductor.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true but R is false
D. A is false but R is true

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