1
NEET 2020 Phase 1
+4
-1
Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?
A
four times
B
one-fourth
C
zero
D
doubled
2
NEET 2020 Phase 1
+4
-1
Light with an average flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence having surface area 20 cm2. The energy received by the surface during time span of 1 minute is :
A
12 $$\times$$ 103 J
B
24 $$\times$$ 103 J
C
48 $$\times$$ 103 J
D
10 $$\times$$ 103 J
3
NEET 2020 Phase 1
+4
-1
An electron is accelerated from rest through a potential difference of V volt. If the de-Broglie wavelength of the electron is 1.227 $$\times$$ 10-2 nm, the potential difference is :
A
102 V
B
103 V
C
104 V
D
10 V
4
NEET 2019
+4
-1
An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is (nearly) : (me = 9 $$\times$$ 10–31 kg)
A
12.2 × 10–12 m
B
12.2 × 10–13 m
C
12.2 × 10–14 m
D
12.2 nm
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