neutrons electrons charge 20 14 10 3+ 18 B. 32S2- C. 32S D. 32S 27 A13+ 24N3+ 27
ID: 697042 • Letter: N
Question
neutrons electrons charge 20 14 10 3+ 18 B. 32S2- C. 32S D. 32S 27 A13+ 24N3+ 27 A13+ 24N3+ Potassium metal has a threshold energy of 3.58 x 10-19 J. Which colors of visible light are capable of ejecting an electron from potassium? color | , nm | red V, Hz 4.62 x 1014 650 nm yellow570 nm 475 nm 5.26 x 1014 blue 6.32 x 1014 red and vellow B. red only C. red, yellow and blue D. yellow and blue E. blue only -34 6.626 x S.40 x1 American professional tennis player John Isner holds the world record for the fastest serve in a
Explanation / Answer
10) Energy of photon = 3.8x10-19 J
Thus the frequency of photon = E/h
= 3.8x10-19 J/6.626x10-34J.sec
=5.734x1014
As the frequency is closer to yellow but greater than in the color corresponding would be yellow and blue.
Correct option is YELLOW AND BLUE OPTION D
10) OPTIONC
Fe+3 has most unpaired electrons
its configuration [Ar] 3d5 with 5 unpaired electrons
Zn has [Ar] 3s2 3p63d10 4s2
Co+2 has [Ar] 3s2 3p63d7
Rb+has [Kr] and
Cr has [Ar] 3s2 3d5 4s1 configurations.
13) As the length is marked 18.957 m, the smallest marking is 0.001 m ( three places after decimal) .
15) the wavlength of photon = 425 nm
Energy of each photon = E = hc/ wavlength
=[ 6.626x10-34 J.sec x 3.0x108m/sec ]/ 425x10-10 m
= 4.677x10-16 j
the burst has 0.518 moles of photons = 0.518x 6.022x1023 photons
Thus total energy = number of phtons x energy of each photon
= 0.518x 6.022x1023 photons x 4.677x10-16 j
= 145.8 kJ
OPtion E
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