Question

Threshold wavelength for photoelectric effect on sodium is 5000 Å. Its work function is

(a) 15 J    

(b) 16  

(c) 4 

(d) 4  

Answer

(c) 4 

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

In a diode valve, the state of saturation can be obtained easily by

(a) High plate voltage and high filament current

(b) Low filament current and high plate voltage

(c) Low plate voltage and high cathode temperature

(d) High filament current and high plate voltage

Two charges each of 1 coulomb are at a distance 1 km  apart, the force between them is

(a)  

(b) 9 

(c)  

(d)  

Sodium and copper have work functions 2.3eV and 4.5eV respectively. Then the ratio of their threshold wavelengths is nearest to

(a) 1: 2

(b) 4 : 1

(c) 2 : 1

(d) 1 : 4

When light is incident on a doubly refracting crystal, two refracted rays-ordinary ray (O-ray) and extra ordinary ray (E-ray) are produced. Then

(a) Both O-ray and E-ray are polarised perpendicular to the plane of incidence

(b) Both O-ray and E-ray are polarised in the plane of incidence

(c) E-ray is polarised perpendicular to the plane of incidence and O-ray in the plane of incidence

(d) E-ray is polarised in the plane of incidence and O-ray perpendicular to the plane of incidence

Particle nature and wave nature of electromagnetic waves and electrons can be shown by

(a) Electron has small mass, deflected by the metal sheet

(b) X-ray is diffracted, reflected by thick metal sheet

(c) Light is refracted and defracted

(d) Photoelectricity and electron microscopy

If the amplitude ratio of two sources producing interference is 3 : 5, the ratio of intensities at maxima and minima is

(a) 25 : 16

(b) 5 : 3

(c) 16 : 1 

(d) 25 : 9

Holes are charge carriers in

(a) Intrinsic semiconductors

(b) P-type semiconductors

(c) Metals

(d) a, b

Assertion  :  NAND or NOR gates are called digital building blocks.

Reason      : The repeated use of NAND (or NOR) gates can produce all the basic or complicated gates.

(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.

Quantity that remains unchanged in a transformer is

(a) Voltage

(b) Current

(c) Frequency

(d) None of the above

At temperature 0K, the germanium behaves as a/ an: