A uniform wire of $16\,\Omega $ is made into the form of a square. Two opposite corners of the square are connected by a wire of resistance $16\,\Omega $. The effective resistance between the other two opposite corners is ............... $\Omega$
A$32$
B$20$
C$8$
D$4$
Medium
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D$4$
d According to the principle of Wheatstone’s bridge, the effective resistance between the given points is $4\,\Omega$.
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Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in $100$ rows, each row stretching horizontally along the body of the fish containing $5000$ electroplaques. The arrangement is suggestively shown below. Each electroplaques has an emf of $0.15\, V$ and internal resistance of $0.25 \,\Omega$ The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of $500 \,\Omega$, the current an eel can produce in water is about .............. $A$
A steady current $I$ is set up in a wire whose cross-sectional area decreases in the direction of the flow of the current. Then, as we examine the narrowing region,
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Consider four conducting materials copper, tungsten, mercury and aluminium with resistivity $\rho_{ C }, \rho_{ T }, \rho_{ M }$ and $\rho_{ A }$ espectively Then:
A heater is designed to operate with a power of $1000 \mathrm{~W}$ in a $100 \mathrm{~V}$ line. It is connected in combination with a resistance of $10 \Omega$ and a resistance $R$, to a $100 \mathrm{~V}$ mains as shown in figure. For the heater to operate at $62.5 \mathrm{~W}$, the value of $\mathrm{R}$ should be .................. $\Omega$.
A thick wire is stretched so that its length become two times. Assuming that there is no change in its density, then what is the ratio of change in resistance of wire to the initial resistance of wire