154822
When a current changes from $2 \mathrm{~A}$ to $4 \mathrm{~A}$ in $0.05 \mathrm{~s}$ in a coil, induced emf is $8 \mathrm{~V}$. The selfinductance of coil is
1 $0.1 \mathrm{H}$
2 $0.2 \mathrm{H}$
3 $0.4 \mathrm{H}$
4 $0.8 \mathrm{H}$
Explanation:
B Given that, Current $(\mathrm{dI})=4-2=2 \mathrm{~A}$ Total time $(\mathrm{dt})=0.05 \mathrm{sec}$ Induced emf $(\varepsilon)=8 \mathrm{~V}$ We know that, $\mathrm{L}=\frac{\varepsilon}{\mathrm{dI} / \mathrm{dt}}=\frac{8}{\frac{2}{0.05}}=0.2 \mathrm{H}$
CG PET- 2014
Electro Magnetic Induction
154825
In the figure, there are two semi-circles of radii $r_{1}$ and $r_{2}$ in which a current $i$ is flowing. The magnetic induction at centre $O$ will be
C Given, Radius of bigger semicircle $=\mathrm{r}_{1}$ Radius of smaller semicircle $=r_{2}$ Current $=\mathrm{i}$ At centre $\mathrm{O}$ magneitc field $\mathrm{B}=\mathrm{B}_{1}+\mathrm{B}_{2}$ $=\frac{\mu_{0} i}{4 r_{1}}+\frac{\mu_{0} i}{4 r_{2}}$ $\mathrm{B}=\frac{\mu_{\mathrm{o}} \mathrm{i}}{4}\left(\frac{\mathrm{r}_{1}+\mathrm{r}_{2}}{\mathrm{r}_{1} \mathrm{r}_{2}}\right)$
CG PET- 2010
Electro Magnetic Induction
154828
The magnetic flux linked with a coil at any instant $t$ is given by $\phi=5 t^{3}-100 t+300$, the emf induced in the coil after $t=2 s$ is
1 $-40 \mathrm{~V}$
2 $40 \mathrm{~V}$
3 $140 \mathrm{~V}$
4 $300 \mathrm{~V}$
Explanation:
B Given, Magnetic flux $(\phi)=5 t^{3}-100 t+300$ Time $(\mathrm{t})=2 \mathrm{sec}$ $\mathrm{emf}=\frac{-\mathrm{d} \phi}{\mathrm{dt}}$ $\varepsilon=-\frac{\mathrm{d}}{\mathrm{dt}}\left(5 \mathrm{t}^{3}-100 \mathrm{t}+300\right)$ $\varepsilon=-\left(15 \mathrm{t}^{2}-100\right)$ at, $\quad \mathrm{t}=2 \mathrm{sec}$. $\varepsilon=-\left[(15) \times(2)^{2}-100\right]$ $\varepsilon=-(60-100)=40 \mathrm{~V}$ $\varepsilon=40 \mathrm{~V}$
CG PET- 2006
Electro Magnetic Induction
154832
In a coil of self inductance $0.5 \mathrm{H}$, the current varies at a constant rate from zero to $10 \mathrm{~A}$ is $2 \mathrm{~s}$. The emf generated in the coil is
1 $10 \mathrm{~V}$
2 $5 \mathrm{~V}$
3 $2.5 \mathrm{~V}$
4 $1.25 \mathrm{~V}$
Explanation:
C Given that, $\mathrm{L}=0.5 \mathrm{H}$ $\mathrm{dI}=(10-0)=10 \mathrm{~A}$ $\mathrm{dt}=2 \mathrm{sec}$ We know that, $\varepsilon =\mathrm{L} \cdot \frac{\mathrm{dI}}{\mathrm{dt}}$ $=0.5 \times \frac{(10-0)}{2}$ $\varepsilon =2.5 \mathrm{~V}$
154822
When a current changes from $2 \mathrm{~A}$ to $4 \mathrm{~A}$ in $0.05 \mathrm{~s}$ in a coil, induced emf is $8 \mathrm{~V}$. The selfinductance of coil is
1 $0.1 \mathrm{H}$
2 $0.2 \mathrm{H}$
3 $0.4 \mathrm{H}$
4 $0.8 \mathrm{H}$
Explanation:
B Given that, Current $(\mathrm{dI})=4-2=2 \mathrm{~A}$ Total time $(\mathrm{dt})=0.05 \mathrm{sec}$ Induced emf $(\varepsilon)=8 \mathrm{~V}$ We know that, $\mathrm{L}=\frac{\varepsilon}{\mathrm{dI} / \mathrm{dt}}=\frac{8}{\frac{2}{0.05}}=0.2 \mathrm{H}$
CG PET- 2014
Electro Magnetic Induction
154825
In the figure, there are two semi-circles of radii $r_{1}$ and $r_{2}$ in which a current $i$ is flowing. The magnetic induction at centre $O$ will be
C Given, Radius of bigger semicircle $=\mathrm{r}_{1}$ Radius of smaller semicircle $=r_{2}$ Current $=\mathrm{i}$ At centre $\mathrm{O}$ magneitc field $\mathrm{B}=\mathrm{B}_{1}+\mathrm{B}_{2}$ $=\frac{\mu_{0} i}{4 r_{1}}+\frac{\mu_{0} i}{4 r_{2}}$ $\mathrm{B}=\frac{\mu_{\mathrm{o}} \mathrm{i}}{4}\left(\frac{\mathrm{r}_{1}+\mathrm{r}_{2}}{\mathrm{r}_{1} \mathrm{r}_{2}}\right)$
CG PET- 2010
Electro Magnetic Induction
154828
The magnetic flux linked with a coil at any instant $t$ is given by $\phi=5 t^{3}-100 t+300$, the emf induced in the coil after $t=2 s$ is
1 $-40 \mathrm{~V}$
2 $40 \mathrm{~V}$
3 $140 \mathrm{~V}$
4 $300 \mathrm{~V}$
Explanation:
B Given, Magnetic flux $(\phi)=5 t^{3}-100 t+300$ Time $(\mathrm{t})=2 \mathrm{sec}$ $\mathrm{emf}=\frac{-\mathrm{d} \phi}{\mathrm{dt}}$ $\varepsilon=-\frac{\mathrm{d}}{\mathrm{dt}}\left(5 \mathrm{t}^{3}-100 \mathrm{t}+300\right)$ $\varepsilon=-\left(15 \mathrm{t}^{2}-100\right)$ at, $\quad \mathrm{t}=2 \mathrm{sec}$. $\varepsilon=-\left[(15) \times(2)^{2}-100\right]$ $\varepsilon=-(60-100)=40 \mathrm{~V}$ $\varepsilon=40 \mathrm{~V}$
CG PET- 2006
Electro Magnetic Induction
154832
In a coil of self inductance $0.5 \mathrm{H}$, the current varies at a constant rate from zero to $10 \mathrm{~A}$ is $2 \mathrm{~s}$. The emf generated in the coil is
1 $10 \mathrm{~V}$
2 $5 \mathrm{~V}$
3 $2.5 \mathrm{~V}$
4 $1.25 \mathrm{~V}$
Explanation:
C Given that, $\mathrm{L}=0.5 \mathrm{H}$ $\mathrm{dI}=(10-0)=10 \mathrm{~A}$ $\mathrm{dt}=2 \mathrm{sec}$ We know that, $\varepsilon =\mathrm{L} \cdot \frac{\mathrm{dI}}{\mathrm{dt}}$ $=0.5 \times \frac{(10-0)}{2}$ $\varepsilon =2.5 \mathrm{~V}$
154822
When a current changes from $2 \mathrm{~A}$ to $4 \mathrm{~A}$ in $0.05 \mathrm{~s}$ in a coil, induced emf is $8 \mathrm{~V}$. The selfinductance of coil is
1 $0.1 \mathrm{H}$
2 $0.2 \mathrm{H}$
3 $0.4 \mathrm{H}$
4 $0.8 \mathrm{H}$
Explanation:
B Given that, Current $(\mathrm{dI})=4-2=2 \mathrm{~A}$ Total time $(\mathrm{dt})=0.05 \mathrm{sec}$ Induced emf $(\varepsilon)=8 \mathrm{~V}$ We know that, $\mathrm{L}=\frac{\varepsilon}{\mathrm{dI} / \mathrm{dt}}=\frac{8}{\frac{2}{0.05}}=0.2 \mathrm{H}$
CG PET- 2014
Electro Magnetic Induction
154825
In the figure, there are two semi-circles of radii $r_{1}$ and $r_{2}$ in which a current $i$ is flowing. The magnetic induction at centre $O$ will be
C Given, Radius of bigger semicircle $=\mathrm{r}_{1}$ Radius of smaller semicircle $=r_{2}$ Current $=\mathrm{i}$ At centre $\mathrm{O}$ magneitc field $\mathrm{B}=\mathrm{B}_{1}+\mathrm{B}_{2}$ $=\frac{\mu_{0} i}{4 r_{1}}+\frac{\mu_{0} i}{4 r_{2}}$ $\mathrm{B}=\frac{\mu_{\mathrm{o}} \mathrm{i}}{4}\left(\frac{\mathrm{r}_{1}+\mathrm{r}_{2}}{\mathrm{r}_{1} \mathrm{r}_{2}}\right)$
CG PET- 2010
Electro Magnetic Induction
154828
The magnetic flux linked with a coil at any instant $t$ is given by $\phi=5 t^{3}-100 t+300$, the emf induced in the coil after $t=2 s$ is
1 $-40 \mathrm{~V}$
2 $40 \mathrm{~V}$
3 $140 \mathrm{~V}$
4 $300 \mathrm{~V}$
Explanation:
B Given, Magnetic flux $(\phi)=5 t^{3}-100 t+300$ Time $(\mathrm{t})=2 \mathrm{sec}$ $\mathrm{emf}=\frac{-\mathrm{d} \phi}{\mathrm{dt}}$ $\varepsilon=-\frac{\mathrm{d}}{\mathrm{dt}}\left(5 \mathrm{t}^{3}-100 \mathrm{t}+300\right)$ $\varepsilon=-\left(15 \mathrm{t}^{2}-100\right)$ at, $\quad \mathrm{t}=2 \mathrm{sec}$. $\varepsilon=-\left[(15) \times(2)^{2}-100\right]$ $\varepsilon=-(60-100)=40 \mathrm{~V}$ $\varepsilon=40 \mathrm{~V}$
CG PET- 2006
Electro Magnetic Induction
154832
In a coil of self inductance $0.5 \mathrm{H}$, the current varies at a constant rate from zero to $10 \mathrm{~A}$ is $2 \mathrm{~s}$. The emf generated in the coil is
1 $10 \mathrm{~V}$
2 $5 \mathrm{~V}$
3 $2.5 \mathrm{~V}$
4 $1.25 \mathrm{~V}$
Explanation:
C Given that, $\mathrm{L}=0.5 \mathrm{H}$ $\mathrm{dI}=(10-0)=10 \mathrm{~A}$ $\mathrm{dt}=2 \mathrm{sec}$ We know that, $\varepsilon =\mathrm{L} \cdot \frac{\mathrm{dI}}{\mathrm{dt}}$ $=0.5 \times \frac{(10-0)}{2}$ $\varepsilon =2.5 \mathrm{~V}$
154822
When a current changes from $2 \mathrm{~A}$ to $4 \mathrm{~A}$ in $0.05 \mathrm{~s}$ in a coil, induced emf is $8 \mathrm{~V}$. The selfinductance of coil is
1 $0.1 \mathrm{H}$
2 $0.2 \mathrm{H}$
3 $0.4 \mathrm{H}$
4 $0.8 \mathrm{H}$
Explanation:
B Given that, Current $(\mathrm{dI})=4-2=2 \mathrm{~A}$ Total time $(\mathrm{dt})=0.05 \mathrm{sec}$ Induced emf $(\varepsilon)=8 \mathrm{~V}$ We know that, $\mathrm{L}=\frac{\varepsilon}{\mathrm{dI} / \mathrm{dt}}=\frac{8}{\frac{2}{0.05}}=0.2 \mathrm{H}$
CG PET- 2014
Electro Magnetic Induction
154825
In the figure, there are two semi-circles of radii $r_{1}$ and $r_{2}$ in which a current $i$ is flowing. The magnetic induction at centre $O$ will be
C Given, Radius of bigger semicircle $=\mathrm{r}_{1}$ Radius of smaller semicircle $=r_{2}$ Current $=\mathrm{i}$ At centre $\mathrm{O}$ magneitc field $\mathrm{B}=\mathrm{B}_{1}+\mathrm{B}_{2}$ $=\frac{\mu_{0} i}{4 r_{1}}+\frac{\mu_{0} i}{4 r_{2}}$ $\mathrm{B}=\frac{\mu_{\mathrm{o}} \mathrm{i}}{4}\left(\frac{\mathrm{r}_{1}+\mathrm{r}_{2}}{\mathrm{r}_{1} \mathrm{r}_{2}}\right)$
CG PET- 2010
Electro Magnetic Induction
154828
The magnetic flux linked with a coil at any instant $t$ is given by $\phi=5 t^{3}-100 t+300$, the emf induced in the coil after $t=2 s$ is
1 $-40 \mathrm{~V}$
2 $40 \mathrm{~V}$
3 $140 \mathrm{~V}$
4 $300 \mathrm{~V}$
Explanation:
B Given, Magnetic flux $(\phi)=5 t^{3}-100 t+300$ Time $(\mathrm{t})=2 \mathrm{sec}$ $\mathrm{emf}=\frac{-\mathrm{d} \phi}{\mathrm{dt}}$ $\varepsilon=-\frac{\mathrm{d}}{\mathrm{dt}}\left(5 \mathrm{t}^{3}-100 \mathrm{t}+300\right)$ $\varepsilon=-\left(15 \mathrm{t}^{2}-100\right)$ at, $\quad \mathrm{t}=2 \mathrm{sec}$. $\varepsilon=-\left[(15) \times(2)^{2}-100\right]$ $\varepsilon=-(60-100)=40 \mathrm{~V}$ $\varepsilon=40 \mathrm{~V}$
CG PET- 2006
Electro Magnetic Induction
154832
In a coil of self inductance $0.5 \mathrm{H}$, the current varies at a constant rate from zero to $10 \mathrm{~A}$ is $2 \mathrm{~s}$. The emf generated in the coil is
1 $10 \mathrm{~V}$
2 $5 \mathrm{~V}$
3 $2.5 \mathrm{~V}$
4 $1.25 \mathrm{~V}$
Explanation:
C Given that, $\mathrm{L}=0.5 \mathrm{H}$ $\mathrm{dI}=(10-0)=10 \mathrm{~A}$ $\mathrm{dt}=2 \mathrm{sec}$ We know that, $\varepsilon =\mathrm{L} \cdot \frac{\mathrm{dI}}{\mathrm{dt}}$ $=0.5 \times \frac{(10-0)}{2}$ $\varepsilon =2.5 \mathrm{~V}$
