NEET Test Series from KOTA - 10 Papers In MS WORD
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TEST SERIES (PHYSICS FST)
263949
Water does not wet an oily glass because:
1 Cohesive force of oil >>adhesive force between oil and glass
2 Cohesive force of oil > cohesive force of water
3 Oilattracts water
4 Cohesive force for water > adhesive force between water and oil molecules
Explanation:
d At critical temperature ( \(\mathrm{T}_{\mathrm{c}}=370^{\circ} \mathrm{C}=643 \mathrm{~K}\) ), the surface tension of water is zero.
**NCERT-XI-II-193**
TEST SERIES (PHYSICS FST)
263950
When green light is incident on the surface of metal, it emits photo-electrons but there is no such emission with yellow colour light. Which one of the colour can produce emission of photoelectrons
1 Orange
2 Red
3 Indigo
4 None of these
Explanation:
c Wave length of green light is threshold wave length. Hence for emission of electron, wave length of incident light < wavelength of green light. VIBGYOR \(E_G>E_V\) \(\Rightarrow E_1>E_6\)
1 Cohesive force of oil >>adhesive force between oil and glass
2 Cohesive force of oil > cohesive force of water
3 Oilattracts water
4 Cohesive force for water > adhesive force between water and oil molecules
Explanation:
d At critical temperature ( \(\mathrm{T}_{\mathrm{c}}=370^{\circ} \mathrm{C}=643 \mathrm{~K}\) ), the surface tension of water is zero.
**NCERT-XI-II-193**
TEST SERIES (PHYSICS FST)
263950
When green light is incident on the surface of metal, it emits photo-electrons but there is no such emission with yellow colour light. Which one of the colour can produce emission of photoelectrons
1 Orange
2 Red
3 Indigo
4 None of these
Explanation:
c Wave length of green light is threshold wave length. Hence for emission of electron, wave length of incident light < wavelength of green light. VIBGYOR \(E_G>E_V\) \(\Rightarrow E_1>E_6\)