Law of Radioactive decay
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NUCLEAR PHYSICS

147876 The half life of a radioactive element is 3.8 days. The fraction left after 19 days will be

1 0.124
2 0.062
3 0.093
4 0.031
NUCLEAR PHYSICS

147878 The $K_{\alpha}$ and $K_{\beta} X$ - rays of molybdenum have wavelengths $0.71 \AA$ and $0.63 \AA$ respectively. Then the wavelength of $L_{\alpha}$ of molybdenum will be.

1 $0.66 \AA$
2 $0.55 \AA$
3 $5.59 \AA$
4 $10.55 \AA$
NUCLEAR PHYSICS

147879 A radioactive sample of half-life 10 days contains $1000 x$ nuclei. Number of original nuclei present after 5 days is :

1 $707 x$
2 $750 x$
3 $500 \mathrm{x}$
4 $250 x$
NUCLEAR PHYSICS

147880 The half-life of a radioactive substance is 20 min. The time taken between $50 \%$ decay and $87.5 \%$ decay of the substance will be :

1 $25 \mathrm{~min}$
2 $30 \mathrm{~min}$
3 $10 \mathrm{~min}$
4 $40 \mathrm{~min}$
NUCLEAR PHYSICS

147876 The half life of a radioactive element is 3.8 days. The fraction left after 19 days will be

1 0.124
2 0.062
3 0.093
4 0.031
NUCLEAR PHYSICS

147878 The $K_{\alpha}$ and $K_{\beta} X$ - rays of molybdenum have wavelengths $0.71 \AA$ and $0.63 \AA$ respectively. Then the wavelength of $L_{\alpha}$ of molybdenum will be.

1 $0.66 \AA$
2 $0.55 \AA$
3 $5.59 \AA$
4 $10.55 \AA$
NUCLEAR PHYSICS

147879 A radioactive sample of half-life 10 days contains $1000 x$ nuclei. Number of original nuclei present after 5 days is :

1 $707 x$
2 $750 x$
3 $500 \mathrm{x}$
4 $250 x$
NUCLEAR PHYSICS

147880 The half-life of a radioactive substance is 20 min. The time taken between $50 \%$ decay and $87.5 \%$ decay of the substance will be :

1 $25 \mathrm{~min}$
2 $30 \mathrm{~min}$
3 $10 \mathrm{~min}$
4 $40 \mathrm{~min}$
NUCLEAR PHYSICS

147876 The half life of a radioactive element is 3.8 days. The fraction left after 19 days will be

1 0.124
2 0.062
3 0.093
4 0.031
NUCLEAR PHYSICS

147878 The $K_{\alpha}$ and $K_{\beta} X$ - rays of molybdenum have wavelengths $0.71 \AA$ and $0.63 \AA$ respectively. Then the wavelength of $L_{\alpha}$ of molybdenum will be.

1 $0.66 \AA$
2 $0.55 \AA$
3 $5.59 \AA$
4 $10.55 \AA$
NUCLEAR PHYSICS

147879 A radioactive sample of half-life 10 days contains $1000 x$ nuclei. Number of original nuclei present after 5 days is :

1 $707 x$
2 $750 x$
3 $500 \mathrm{x}$
4 $250 x$
NUCLEAR PHYSICS

147880 The half-life of a radioactive substance is 20 min. The time taken between $50 \%$ decay and $87.5 \%$ decay of the substance will be :

1 $25 \mathrm{~min}$
2 $30 \mathrm{~min}$
3 $10 \mathrm{~min}$
4 $40 \mathrm{~min}$
NUCLEAR PHYSICS

147876 The half life of a radioactive element is 3.8 days. The fraction left after 19 days will be

1 0.124
2 0.062
3 0.093
4 0.031
NUCLEAR PHYSICS

147878 The $K_{\alpha}$ and $K_{\beta} X$ - rays of molybdenum have wavelengths $0.71 \AA$ and $0.63 \AA$ respectively. Then the wavelength of $L_{\alpha}$ of molybdenum will be.

1 $0.66 \AA$
2 $0.55 \AA$
3 $5.59 \AA$
4 $10.55 \AA$
NUCLEAR PHYSICS

147879 A radioactive sample of half-life 10 days contains $1000 x$ nuclei. Number of original nuclei present after 5 days is :

1 $707 x$
2 $750 x$
3 $500 \mathrm{x}$
4 $250 x$
NUCLEAR PHYSICS

147880 The half-life of a radioactive substance is 20 min. The time taken between $50 \%$ decay and $87.5 \%$ decay of the substance will be :

1 $25 \mathrm{~min}$
2 $30 \mathrm{~min}$
3 $10 \mathrm{~min}$
4 $40 \mathrm{~min}$