357614
A \(200\,W\) sodium street lamp emits yellow light of wavelength \({0.6 \mu {m}}\). Assuming it to be \({25 \%}\) efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is
1 \({62 \times 10^{20}}\)
2 \({3 \times 10^{19}}\)
3 \({1.5 \times 10^{20}}\)
4 \({6 \times 10^{18}}\)
Explanation:
Power converted to light \({P_{1}=\dfrac{25}{100} \times 200=50 {~W}}\) Energy of photon \({E=\dfrac{h c}{\lambda}=3.31 \times 10^{-20}}\) Now, \({{n}=\dfrac{\text { Amount of power converted to light }}{\text { Energy of photon }}}\) \({=\dfrac{50}{33.1 \times 10^{-20}}=1.5 \times 10^{20}}\)
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357615
The rest mass of photon is:
1 zero
2 infinite \((\infty)\)
3 between 0 and \(\infty\)
4 equal to that of an electron
Explanation:
Conceptual Question
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357616
A particle of mass \(M\) at rest decays into two particles of masses \(m_{1}\) and \(m_{2}\) having non zero velocities. The ratio of the de - Broglie wavelengths of the particles \(\lambda_{1} / \lambda_{2}\) is
1 \(m_{1} / m_{2}\)
2 \(m_{2} / m_{1}\)
3 1
4 \(\sqrt{m_{2}} / \sqrt{m_{1}}\)
Explanation:
As no external force acts on system momentum of system remains conserved \(0=m_{1} v_{1}-m_{2} v_{2}\) \(m_{1} v_{1}=m_{2} v_{2} \Rightarrow\left(\dfrac{m_{2} v_{2}}{m_{1} v_{1}}\right)=1\) \(\dfrac{\lambda_{1}}{\lambda_{2}}=\dfrac{\dfrac{h}{m_{1} v_{1}}}{\dfrac{h}{m_{2} v_{2}}}=1\)
357614
A \(200\,W\) sodium street lamp emits yellow light of wavelength \({0.6 \mu {m}}\). Assuming it to be \({25 \%}\) efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is
1 \({62 \times 10^{20}}\)
2 \({3 \times 10^{19}}\)
3 \({1.5 \times 10^{20}}\)
4 \({6 \times 10^{18}}\)
Explanation:
Power converted to light \({P_{1}=\dfrac{25}{100} \times 200=50 {~W}}\) Energy of photon \({E=\dfrac{h c}{\lambda}=3.31 \times 10^{-20}}\) Now, \({{n}=\dfrac{\text { Amount of power converted to light }}{\text { Energy of photon }}}\) \({=\dfrac{50}{33.1 \times 10^{-20}}=1.5 \times 10^{20}}\)
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357615
The rest mass of photon is:
1 zero
2 infinite \((\infty)\)
3 between 0 and \(\infty\)
4 equal to that of an electron
Explanation:
Conceptual Question
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357616
A particle of mass \(M\) at rest decays into two particles of masses \(m_{1}\) and \(m_{2}\) having non zero velocities. The ratio of the de - Broglie wavelengths of the particles \(\lambda_{1} / \lambda_{2}\) is
1 \(m_{1} / m_{2}\)
2 \(m_{2} / m_{1}\)
3 1
4 \(\sqrt{m_{2}} / \sqrt{m_{1}}\)
Explanation:
As no external force acts on system momentum of system remains conserved \(0=m_{1} v_{1}-m_{2} v_{2}\) \(m_{1} v_{1}=m_{2} v_{2} \Rightarrow\left(\dfrac{m_{2} v_{2}}{m_{1} v_{1}}\right)=1\) \(\dfrac{\lambda_{1}}{\lambda_{2}}=\dfrac{\dfrac{h}{m_{1} v_{1}}}{\dfrac{h}{m_{2} v_{2}}}=1\)
357614
A \(200\,W\) sodium street lamp emits yellow light of wavelength \({0.6 \mu {m}}\). Assuming it to be \({25 \%}\) efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is
1 \({62 \times 10^{20}}\)
2 \({3 \times 10^{19}}\)
3 \({1.5 \times 10^{20}}\)
4 \({6 \times 10^{18}}\)
Explanation:
Power converted to light \({P_{1}=\dfrac{25}{100} \times 200=50 {~W}}\) Energy of photon \({E=\dfrac{h c}{\lambda}=3.31 \times 10^{-20}}\) Now, \({{n}=\dfrac{\text { Amount of power converted to light }}{\text { Energy of photon }}}\) \({=\dfrac{50}{33.1 \times 10^{-20}}=1.5 \times 10^{20}}\)
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357615
The rest mass of photon is:
1 zero
2 infinite \((\infty)\)
3 between 0 and \(\infty\)
4 equal to that of an electron
Explanation:
Conceptual Question
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357616
A particle of mass \(M\) at rest decays into two particles of masses \(m_{1}\) and \(m_{2}\) having non zero velocities. The ratio of the de - Broglie wavelengths of the particles \(\lambda_{1} / \lambda_{2}\) is
1 \(m_{1} / m_{2}\)
2 \(m_{2} / m_{1}\)
3 1
4 \(\sqrt{m_{2}} / \sqrt{m_{1}}\)
Explanation:
As no external force acts on system momentum of system remains conserved \(0=m_{1} v_{1}-m_{2} v_{2}\) \(m_{1} v_{1}=m_{2} v_{2} \Rightarrow\left(\dfrac{m_{2} v_{2}}{m_{1} v_{1}}\right)=1\) \(\dfrac{\lambda_{1}}{\lambda_{2}}=\dfrac{\dfrac{h}{m_{1} v_{1}}}{\dfrac{h}{m_{2} v_{2}}}=1\)
357614
A \(200\,W\) sodium street lamp emits yellow light of wavelength \({0.6 \mu {m}}\). Assuming it to be \({25 \%}\) efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is
1 \({62 \times 10^{20}}\)
2 \({3 \times 10^{19}}\)
3 \({1.5 \times 10^{20}}\)
4 \({6 \times 10^{18}}\)
Explanation:
Power converted to light \({P_{1}=\dfrac{25}{100} \times 200=50 {~W}}\) Energy of photon \({E=\dfrac{h c}{\lambda}=3.31 \times 10^{-20}}\) Now, \({{n}=\dfrac{\text { Amount of power converted to light }}{\text { Energy of photon }}}\) \({=\dfrac{50}{33.1 \times 10^{-20}}=1.5 \times 10^{20}}\)
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357615
The rest mass of photon is:
1 zero
2 infinite \((\infty)\)
3 between 0 and \(\infty\)
4 equal to that of an electron
Explanation:
Conceptual Question
PHXII11:DUAL NATURE OF RADIATION AND MATTER
357616
A particle of mass \(M\) at rest decays into two particles of masses \(m_{1}\) and \(m_{2}\) having non zero velocities. The ratio of the de - Broglie wavelengths of the particles \(\lambda_{1} / \lambda_{2}\) is
1 \(m_{1} / m_{2}\)
2 \(m_{2} / m_{1}\)
3 1
4 \(\sqrt{m_{2}} / \sqrt{m_{1}}\)
Explanation:
As no external force acts on system momentum of system remains conserved \(0=m_{1} v_{1}-m_{2} v_{2}\) \(m_{1} v_{1}=m_{2} v_{2} \Rightarrow\left(\dfrac{m_{2} v_{2}}{m_{1} v_{1}}\right)=1\) \(\dfrac{\lambda_{1}}{\lambda_{2}}=\dfrac{\dfrac{h}{m_{1} v_{1}}}{\dfrac{h}{m_{2} v_{2}}}=1\)