01. Poynting vector, Energy transported by EM wave, Energy density
Electromagnetic Wave

155609 The ratio of contributions made by the electric field and magnetic field components, to the intensity of a electromagnetic wave is (where, $c$ $=$ speed of electromagnetic waves)

1 $1: 1$
2 $1: \mathrm{c}$
3 $1: c^{2}$
4 $\mathrm{c}: 1$
Electromagnetic Wave

155610 The amplitude of electric field of a plane electromagnetic wave propagating along $Z$-axis is $4 \mathrm{Vm}^{-\mathrm{P}}$. It varies with time. The average energy density of the magnetic field in $\mathrm{Jm}^{-3}$ is $\left(\varepsilon_{0}=8.854 \times 10^{-12} C^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}\right)$

1 $25.4 \times 10^{-12}$
2 $30.5 \times 10^{-12}$
3 $45.4 \times 10^{-12}$
4 $35.4 \times 10^{-12}$
Electromagnetic Wave

155611 An electromagnetic wave of frequency $1 \times 10^{14}$ $\mathrm{Hz}$ is propagating along $\mathrm{z}$-axis. The amplitude of electric field is $4 \mathrm{Vm}^{-1}$, then energy density of the electric field will be (Permittivity of free space $=8.8 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}$ )

1 $35.2 \times 10^{-13} \mathrm{Jm}^{-3}$
2 $70.4 \times 10^{-13} \mathrm{Jm}^{-3}$
3 $70.4 \times 10^{-12} \mathrm{Jm}^{-3}$
4 $35.2 \times 10^{-12} \mathrm{Jm}^{-3}$
Electromagnetic Wave

155612 A point of source of electromagnetic radiation has an average power output of $960 \mathrm{~W}$. The peak value of the electric field at a distance 400 $\mathrm{cm}$ from the source is

1 $60 \mathrm{Vm}^{-1}$
2 $120 \mathrm{Vm}^{-1}$
3 $30 \mathrm{Vm}^{-1}$
4 $180 \mathrm{Vm}^{-1}$
Electromagnetic Wave

155615 The energies required to set up in a cube of side $10 \mathrm{~cm}$
(i) A uniform electric field of $10^{7} \mathrm{Vm}^{-1}$ and
(ii) A uniform magnetic field if $0.25 \mathrm{Wbm}^{-2}$ are respectively about
$\left(\mu_{0}=4 \pi \times 10^{-7} \mathrm{Hm}^{-1}, \varepsilon_{0}=8.9 \times 10^{-12} \mathrm{Fm}^{-1}\right)$

1 $0.445 \mathrm{~J}, 25 \mathrm{~J}$
2 $4.45 \mathrm{~J}, 2.5 \mathrm{~J}$
3 $44.5 \mathrm{~J}, 25 \mathrm{~J}$
4 $0.44 \mathrm{~J}, 2.5 \mathrm{~J}$
Electromagnetic Wave

155609 The ratio of contributions made by the electric field and magnetic field components, to the intensity of a electromagnetic wave is (where, $c$ $=$ speed of electromagnetic waves)

1 $1: 1$
2 $1: \mathrm{c}$
3 $1: c^{2}$
4 $\mathrm{c}: 1$
Electromagnetic Wave

155610 The amplitude of electric field of a plane electromagnetic wave propagating along $Z$-axis is $4 \mathrm{Vm}^{-\mathrm{P}}$. It varies with time. The average energy density of the magnetic field in $\mathrm{Jm}^{-3}$ is $\left(\varepsilon_{0}=8.854 \times 10^{-12} C^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}\right)$

1 $25.4 \times 10^{-12}$
2 $30.5 \times 10^{-12}$
3 $45.4 \times 10^{-12}$
4 $35.4 \times 10^{-12}$
Electromagnetic Wave

155611 An electromagnetic wave of frequency $1 \times 10^{14}$ $\mathrm{Hz}$ is propagating along $\mathrm{z}$-axis. The amplitude of electric field is $4 \mathrm{Vm}^{-1}$, then energy density of the electric field will be (Permittivity of free space $=8.8 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}$ )

1 $35.2 \times 10^{-13} \mathrm{Jm}^{-3}$
2 $70.4 \times 10^{-13} \mathrm{Jm}^{-3}$
3 $70.4 \times 10^{-12} \mathrm{Jm}^{-3}$
4 $35.2 \times 10^{-12} \mathrm{Jm}^{-3}$
Electromagnetic Wave

155612 A point of source of electromagnetic radiation has an average power output of $960 \mathrm{~W}$. The peak value of the electric field at a distance 400 $\mathrm{cm}$ from the source is

1 $60 \mathrm{Vm}^{-1}$
2 $120 \mathrm{Vm}^{-1}$
3 $30 \mathrm{Vm}^{-1}$
4 $180 \mathrm{Vm}^{-1}$
Electromagnetic Wave

155615 The energies required to set up in a cube of side $10 \mathrm{~cm}$
(i) A uniform electric field of $10^{7} \mathrm{Vm}^{-1}$ and
(ii) A uniform magnetic field if $0.25 \mathrm{Wbm}^{-2}$ are respectively about
$\left(\mu_{0}=4 \pi \times 10^{-7} \mathrm{Hm}^{-1}, \varepsilon_{0}=8.9 \times 10^{-12} \mathrm{Fm}^{-1}\right)$

1 $0.445 \mathrm{~J}, 25 \mathrm{~J}$
2 $4.45 \mathrm{~J}, 2.5 \mathrm{~J}$
3 $44.5 \mathrm{~J}, 25 \mathrm{~J}$
4 $0.44 \mathrm{~J}, 2.5 \mathrm{~J}$
Electromagnetic Wave

155609 The ratio of contributions made by the electric field and magnetic field components, to the intensity of a electromagnetic wave is (where, $c$ $=$ speed of electromagnetic waves)

1 $1: 1$
2 $1: \mathrm{c}$
3 $1: c^{2}$
4 $\mathrm{c}: 1$
Electromagnetic Wave

155610 The amplitude of electric field of a plane electromagnetic wave propagating along $Z$-axis is $4 \mathrm{Vm}^{-\mathrm{P}}$. It varies with time. The average energy density of the magnetic field in $\mathrm{Jm}^{-3}$ is $\left(\varepsilon_{0}=8.854 \times 10^{-12} C^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}\right)$

1 $25.4 \times 10^{-12}$
2 $30.5 \times 10^{-12}$
3 $45.4 \times 10^{-12}$
4 $35.4 \times 10^{-12}$
Electromagnetic Wave

155611 An electromagnetic wave of frequency $1 \times 10^{14}$ $\mathrm{Hz}$ is propagating along $\mathrm{z}$-axis. The amplitude of electric field is $4 \mathrm{Vm}^{-1}$, then energy density of the electric field will be (Permittivity of free space $=8.8 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}$ )

1 $35.2 \times 10^{-13} \mathrm{Jm}^{-3}$
2 $70.4 \times 10^{-13} \mathrm{Jm}^{-3}$
3 $70.4 \times 10^{-12} \mathrm{Jm}^{-3}$
4 $35.2 \times 10^{-12} \mathrm{Jm}^{-3}$
Electromagnetic Wave

155612 A point of source of electromagnetic radiation has an average power output of $960 \mathrm{~W}$. The peak value of the electric field at a distance 400 $\mathrm{cm}$ from the source is

1 $60 \mathrm{Vm}^{-1}$
2 $120 \mathrm{Vm}^{-1}$
3 $30 \mathrm{Vm}^{-1}$
4 $180 \mathrm{Vm}^{-1}$
Electromagnetic Wave

155615 The energies required to set up in a cube of side $10 \mathrm{~cm}$
(i) A uniform electric field of $10^{7} \mathrm{Vm}^{-1}$ and
(ii) A uniform magnetic field if $0.25 \mathrm{Wbm}^{-2}$ are respectively about
$\left(\mu_{0}=4 \pi \times 10^{-7} \mathrm{Hm}^{-1}, \varepsilon_{0}=8.9 \times 10^{-12} \mathrm{Fm}^{-1}\right)$

1 $0.445 \mathrm{~J}, 25 \mathrm{~J}$
2 $4.45 \mathrm{~J}, 2.5 \mathrm{~J}$
3 $44.5 \mathrm{~J}, 25 \mathrm{~J}$
4 $0.44 \mathrm{~J}, 2.5 \mathrm{~J}$
Electromagnetic Wave

155609 The ratio of contributions made by the electric field and magnetic field components, to the intensity of a electromagnetic wave is (where, $c$ $=$ speed of electromagnetic waves)

1 $1: 1$
2 $1: \mathrm{c}$
3 $1: c^{2}$
4 $\mathrm{c}: 1$
Electromagnetic Wave

155610 The amplitude of electric field of a plane electromagnetic wave propagating along $Z$-axis is $4 \mathrm{Vm}^{-\mathrm{P}}$. It varies with time. The average energy density of the magnetic field in $\mathrm{Jm}^{-3}$ is $\left(\varepsilon_{0}=8.854 \times 10^{-12} C^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}\right)$

1 $25.4 \times 10^{-12}$
2 $30.5 \times 10^{-12}$
3 $45.4 \times 10^{-12}$
4 $35.4 \times 10^{-12}$
Electromagnetic Wave

155611 An electromagnetic wave of frequency $1 \times 10^{14}$ $\mathrm{Hz}$ is propagating along $\mathrm{z}$-axis. The amplitude of electric field is $4 \mathrm{Vm}^{-1}$, then energy density of the electric field will be (Permittivity of free space $=8.8 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}$ )

1 $35.2 \times 10^{-13} \mathrm{Jm}^{-3}$
2 $70.4 \times 10^{-13} \mathrm{Jm}^{-3}$
3 $70.4 \times 10^{-12} \mathrm{Jm}^{-3}$
4 $35.2 \times 10^{-12} \mathrm{Jm}^{-3}$
Electromagnetic Wave

155612 A point of source of electromagnetic radiation has an average power output of $960 \mathrm{~W}$. The peak value of the electric field at a distance 400 $\mathrm{cm}$ from the source is

1 $60 \mathrm{Vm}^{-1}$
2 $120 \mathrm{Vm}^{-1}$
3 $30 \mathrm{Vm}^{-1}$
4 $180 \mathrm{Vm}^{-1}$
Electromagnetic Wave

155615 The energies required to set up in a cube of side $10 \mathrm{~cm}$
(i) A uniform electric field of $10^{7} \mathrm{Vm}^{-1}$ and
(ii) A uniform magnetic field if $0.25 \mathrm{Wbm}^{-2}$ are respectively about
$\left(\mu_{0}=4 \pi \times 10^{-7} \mathrm{Hm}^{-1}, \varepsilon_{0}=8.9 \times 10^{-12} \mathrm{Fm}^{-1}\right)$

1 $0.445 \mathrm{~J}, 25 \mathrm{~J}$
2 $4.45 \mathrm{~J}, 2.5 \mathrm{~J}$
3 $44.5 \mathrm{~J}, 25 \mathrm{~J}$
4 $0.44 \mathrm{~J}, 2.5 \mathrm{~J}$
Electromagnetic Wave

155609 The ratio of contributions made by the electric field and magnetic field components, to the intensity of a electromagnetic wave is (where, $c$ $=$ speed of electromagnetic waves)

1 $1: 1$
2 $1: \mathrm{c}$
3 $1: c^{2}$
4 $\mathrm{c}: 1$
Electromagnetic Wave

155610 The amplitude of electric field of a plane electromagnetic wave propagating along $Z$-axis is $4 \mathrm{Vm}^{-\mathrm{P}}$. It varies with time. The average energy density of the magnetic field in $\mathrm{Jm}^{-3}$ is $\left(\varepsilon_{0}=8.854 \times 10^{-12} C^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}\right)$

1 $25.4 \times 10^{-12}$
2 $30.5 \times 10^{-12}$
3 $45.4 \times 10^{-12}$
4 $35.4 \times 10^{-12}$
Electromagnetic Wave

155611 An electromagnetic wave of frequency $1 \times 10^{14}$ $\mathrm{Hz}$ is propagating along $\mathrm{z}$-axis. The amplitude of electric field is $4 \mathrm{Vm}^{-1}$, then energy density of the electric field will be (Permittivity of free space $=8.8 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}$ )

1 $35.2 \times 10^{-13} \mathrm{Jm}^{-3}$
2 $70.4 \times 10^{-13} \mathrm{Jm}^{-3}$
3 $70.4 \times 10^{-12} \mathrm{Jm}^{-3}$
4 $35.2 \times 10^{-12} \mathrm{Jm}^{-3}$
Electromagnetic Wave

155612 A point of source of electromagnetic radiation has an average power output of $960 \mathrm{~W}$. The peak value of the electric field at a distance 400 $\mathrm{cm}$ from the source is

1 $60 \mathrm{Vm}^{-1}$
2 $120 \mathrm{Vm}^{-1}$
3 $30 \mathrm{Vm}^{-1}$
4 $180 \mathrm{Vm}^{-1}$
Electromagnetic Wave

155615 The energies required to set up in a cube of side $10 \mathrm{~cm}$
(i) A uniform electric field of $10^{7} \mathrm{Vm}^{-1}$ and
(ii) A uniform magnetic field if $0.25 \mathrm{Wbm}^{-2}$ are respectively about
$\left(\mu_{0}=4 \pi \times 10^{-7} \mathrm{Hm}^{-1}, \varepsilon_{0}=8.9 \times 10^{-12} \mathrm{Fm}^{-1}\right)$

1 $0.445 \mathrm{~J}, 25 \mathrm{~J}$
2 $4.45 \mathrm{~J}, 2.5 \mathrm{~J}$
3 $44.5 \mathrm{~J}, 25 \mathrm{~J}$
4 $0.44 \mathrm{~J}, 2.5 \mathrm{~J}$