List of practice Questions

In the given circuit, an ideal voltmeter connected across the $10\, \Omega$ resistance reads $2V$. The internal resistance $r$, of each cell is :

In the given circuit diagram, the currents, $I_1 = 0.3\,A, I_4 = 0.8\, A$ and $I_5 = 0.4\, A$, are flowing as shown. The currents $I_2,I_3$ and $I_6$,respectively, are :

The Wheatstone bridge shown in Fig. here, gets balanced when the carbon resistor used as $R_1$ has the colour code ( Orange, Red, Brown). The resistors $R_2$ and $R_4$ are $80\Omega $ and $40 \Omega $ respectively. Assuming that the colour code for the carbon resistors gives their accurate values, the colour code for the carbon resistor, used as $R_3$, would be :

When the switch $S$, in the circuit shown, is closed, then the value of current $i$ will be :

The resistance of the meter bridge $AB$ is given figure is $4\Omega$ . With a cell of emf $\varepsilon = 0.5 \;V $ and rheostat resistance $R_h = 2 \; \Omega$ the null point is obtained at some point $J$. When the cell is replaced by another one of emf $\varepsilon = \varepsilon_2$ the same null point $J$ is found for $R_h = 6 \; \Omega$. The emf $\varepsilon_2$ is;

In the circuit shown, a four-wire potentiometer is made of a $400\, cm$ long wire, which extends between $A$ and $B$. The resistance per unit length of the potentiometer wire is $r = 0.01 $ $\Omega/cm$. If an ideal voltmeter is connected as shown with jockey $J$ at $50\, cm$ from end $A$, the expected reading of the voltmeter will be :

A cell of internal resistance r drives current through an external resistance $R$. The power delivered by the cell to the external resistance will be maximum when

An electric dipole is formed by two equal and opposite charges $q$ with separation $d$. The charges have same mass $m$. It is kept in a uniform electric field $E$. If it is slightly rotated from its equilibrium orientation, then its angular frequency $\omega$ is :

What is the common name of the acidic combination of nitric acid and hydrochloric acid that can actually dissolve metals like gold and platinum?

Viacom18 is a popular entertainment network of India. Which of these channels does not belong to Viacom18?

Which of the following liquids demonstrates a convex meniscus when confined within a glass tube?

A hyperbola has its centre at the origin, passes through the point $(4,2)$ and has transverse axis of length $4$ along the x-axis. Then the eccentricity of the hyperbola is :

The isoelectronic set of ions is :

The radius of the largest sphere which fits properly at the centre of the edge of body centred cubic unit cell is : (Edge length is represented by 'a') :

At some location on earth the horizontal component of earth's magnetic field is $18 \times 10^{-6}$ T. At this location, magnetic needle of length $0.12\, m$ and pole strength $1.8\, Am$ is suspended from its mid-point using a thread, it makes $45^{\circ}$ angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is :

Consider the $LR$ circuit shown in the figure. If the switch $S$ is closed at $t = 0$ then the amount of charge that passes through the battery between $t = 0$ and $t = \frac{L}{R}$ is:

For the reaction, ${2A + B \to }$ products, when the concentrations of A and B both where doubled , the rate of the reaction increased from $0.3 \; mol \; L^{-1} s^{-1 }$ to $2.4 \; mol \; L^{-1} s^{-1}$. When the concentration of A alone is doubled, the rate increased from $0.3 \; mol \; L^{-1} s^{-1}$ to $0.6 \; mol \; L^{-1} s^{-1}$ Which one of the following statements is correct ?

A common emitter amplifier circuit, built using an npn transistor, is shown in the figure. Its dc current gain is $250, \,R_C = 1k\Omega$ and $V_{CC} = 10 V$. What is the minimum base current for $V_{CE}$ to reach saturation ?

An example of solid sol is :

Ozone is destroyed by CFCs in the upper stratosphere Ozone holes increase the amount of UV radiation reaching the earth.

If the truth value of the statement $P \to ( \sim p \vee r)$ is false(F), then the truth values of the statements $p, q, r$ are respectively :

The $pH$ of rain water, is approximately :

Which of the following is a thermosetting polymer?

Calculate the accurate osmotic pressure at00Cof a blood serum sample using Lewis equation having freezing point - 053° C